Internal server error, blank nextcloud log, some errors in apache

My Nextcloud install was running fine until a couple of days ago when it started giving me an “Internal Server Error” page when I go to the URL.
I am running the techandme appliance on windows 10 in Virtualbox.
The nextcloud log is blank and the apache log says:

[Wed Jun 20 06:25:07.593536 2018] [mpm_prefork:notice] [pid 1593] AH00163: Apache/2.4.18 (Ubuntu) OpenSSL/1.0.2g configured – resuming normal operations
[Wed Jun 20 06:25:07.593565 2018] [core:notice] [pid 1593] AH00094: Command line: ‘/usr/sbin/apache2’
[Wed Jun 20 17:28:30.791568 2018] [mpm_prefork:notice] [pid 1593] AH00169: caught SIGTERM, shutting down
[Wed Jun 20 17:28:44.922113 2018] [mpm_prefork:notice] [pid 1607] AH00163: Apache/2.4.18 (Ubuntu) OpenSSL/1.0.2g configured – resuming normal operations
[Wed Jun 20 17:28:44.932732 2018] [core:notice] [pid 1607] AH00094: Command line: ‘/usr/sbin/apache2’
[Wed Jun 20 21:20:26.918800 2018] [mpm_prefork:notice] [pid 1607] AH00169: caught SIGTERM, shutting down
[Wed Jun 20 21:20:35.892548 2018] [mpm_prefork:notice] [pid 1597] AH00163: Apache/2.4.18 (Ubuntu) OpenSSL/1.0.2g configured – resuming normal operations
[Wed Jun 20 21:20:35.892884 2018] [core:notice] [pid 1597] AH00094: Command line: ‘/usr/sbin/apache2’

I’ve tried updating to the latest version of Nextcloud using the built in script, but to no avail.

Also, I know almost nothing about using linux (which is why I’m using the appliance) so if you do have a solution, please spell it out for me like I’m an idiot.

Any suggestions on things I might try, or troubleshooting steps?

I guess a typo in the Apache config.

But what would cause the typo. I didn’t make any changes, it was working one minute, then it stopped all of a sudden.

How would I find the typo and fix it?

Could any of these be causing it. These are from [/var/log/syslog]

Jun 21 08:55:23 najand mysqld[1496]: 2018-06-21  8:55:23 140273967785728 [Warning] Access denied for user 'netdata'@'localhost' (using password: NO)
Jun 21 08:55:23 najand mysqld[1496]: message repeated 5 times: [ 2018-06-21  8:55:23 140273967785728 [Warning] Access denied for user 'netdata'@'localhost' (using password: NO)]
Jun 21 08:55:23 najand mysqld[1496]: 2018-06-21  8:55:23 140273967785728 [Warning] Access denied for user 'root'@'localhost' (using password: NO)
Jun 21 08:55:23 najand mysqld[1496]: message repeated 4 times: [ 2018-06-21  8:55:23 140273967785728 [Warning] Access denied for user 'root'@'localhost' (using password: NO)]
Jun 21 08:55:23 najand mysqld[1496]: 2018-06-21  8:55:23 140273967785728 [Warning] Access denied for user 'netdata'@'localhost' (using password: NO)
Jun 21 08:55:23 najand mysqld[1496]: message repeated 4 times: [ 2018-06-21  8:55:23 140273967785728 [Warning] Access denied for user 'netdata'@'localhost' (using password: NO)]
Jun 21 08:56:09 najand systemd-timesyncd[808]: Synchronized to time server 91.189.94.4:123 (ntp.ubuntu.com).
Jun 21 08:56:09 najand systemd[1]: Time has been changed
Jun 21 09:00:02 najand CRON[2995]: (www-data) CMD (php -f /var/www/nextcloud/cron.php > /dev/null 2>&1)

If so, how would I fix this?

Also, I updated some modules using the Webmin interface and apache is giving me these errors now:

[Thu Jun 21 06:25:08.329099 2018] [mpm_prefork:notice] [pid 1597] AH00163: Apache/2.4.18 (Ubuntu) OpenSSL/1.0.2g configured -- resuming normal operations
[Thu Jun 21 06:25:08.329117 2018] [core:notice] [pid 1597] AH00094: Command line: '/usr/sbin/apache2'
[Thu Jun 21 08:40:55.881615 2018] [:error] [pid 20041] [client 24.64.241.226:40043] PHP Fatal error:  Uncaught Doctrine\\DBAL\\DBALException: Failed to connect to the database: An exception occured in driver: SQLSTATE[HY000] [2002] No such file or directory in /var/www/nextcloud/lib/private/DB/Connection.php:64\nStack trace:\n#0 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(429): OC\\DB\\Connection->connect()\n#1 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(389): Doctrine\\DBAL\\Connection->getDatabasePlatformVersion()\n#2 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(328): Doctrine\\DBAL\\Connection->detectDatabasePlatform()\n#3 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(623): Doctrine\\DBAL\\Connection->getDatabasePlatform()\n#4 /var/www/nextcloud/lib/private/DB/Connection.php(151): Doctrine\\DBAL\\Connection->setTransactionIsolation(2)\n#5 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DriverManager.php(172): OC\\DB\\Connection->__construct(Array, Object(Doctrine\\DBAL\\Driver\\PDOMySql\\Driver), Obj in /var/www/nextcloud/lib/private/DB/Connection.php on line 64
[Thu Jun 21 08:40:55.883467 2018] [:error] [pid 20041] [client 24.64.241.226:40043] PHP Fatal error:  Uncaught Doctrine\\DBAL\\DBALException: Failed to connect to the database: An exception occured in driver: SQLSTATE[HY000] [2002] No such file or directory in /var/www/nextcloud/lib/private/DB/Connection.php:64\nStack trace:\n#0 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(429): OC\\DB\\Connection->connect()\n#1 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(389): Doctrine\\DBAL\\Connection->getDatabasePlatformVersion()\n#2 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(328): Doctrine\\DBAL\\Connection->detectDatabasePlatform()\n#3 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(623): Doctrine\\DBAL\\Connection->getDatabasePlatform()\n#4 /var/www/nextcloud/lib/private/DB/Connection.php(151): Doctrine\\DBAL\\Connection->setTransactionIsolation(2)\n#5 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DriverManager.php(172): OC\\DB\\Connection->__construct(Array, Object(Doctrine\\DBAL\\Driver\\PDOMySql\\Driver), Obj in /var/www/nextcloud/lib/private/DB/Connection.php on line 64
[Thu Jun 21 08:40:56.141084 2018] [:error] [pid 21154] [client 24.64.241.226:43898] PHP Fatal error:  Uncaught Doctrine\\DBAL\\DBALException: Failed to connect to the database: An exception occured in driver: SQLSTATE[HY000] [2002] No such file or directory in /var/www/nextcloud/lib/private/DB/Connection.php:64\nStack trace:\n#0 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(429): OC\\DB\\Connection->connect()\n#1 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(389): Doctrine\\DBAL\\Connection->getDatabasePlatformVersion()\n#2 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(328): Doctrine\\DBAL\\Connection->detectDatabasePlatform()\n#3 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(623): Doctrine\\DBAL\\Connection->getDatabasePlatform()\n#4 /var/www/nextcloud/lib/private/DB/Connection.php(151): Doctrine\\DBAL\\Connection->setTransactionIsolation(2)\n#5 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DriverManager.php(172): OC\\DB\\Connection->__construct(Array, Object(Doctrine\\DBAL\\Driver\\PDOMySql\\Driver), Obj in /var/www/nextcloud/lib/private/DB/Connection.php on line 64
[Thu Jun 21 08:40:56.141412 2018] [:error] [pid 21154] [client 24.64.241.226:43898] PHP Fatal error:  Uncaught Doctrine\\DBAL\\DBALException: Failed to connect to the database: An exception occured in driver: SQLSTATE[HY000] [2002] No such file or directory in /var/www/nextcloud/lib/private/DB/Connection.php:64\nStack trace:\n#0 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(429): OC\\DB\\Connection->connect()\n#1 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(389): Doctrine\\DBAL\\Connection->getDatabasePlatformVersion()\n#2 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(328): Doctrine\\DBAL\\Connection->detectDatabasePlatform()\n#3 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(623): Doctrine\\DBAL\\Connection->getDatabasePlatform()\n#4 /var/www/nextcloud/lib/private/DB/Connection.php(151): Doctrine\\DBAL\\Connection->setTransactionIsolation(2)\n#5 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DriverManager.php(172): OC\\DB\\Connection->__construct(Array, Object(Doctrine\\DBAL\\Driver\\PDOMySql\\Driver), Obj in /var/www/nextcloud/lib/private/DB/Connection.php on line 64
[Thu Jun 21 08:40:56.265421 2018] [:error] [pid 20040] [client 24.64.241.226:42512] PHP Fatal error:  Uncaught Doctrine\\DBAL\\DBALException: Failed to connect to the database: An exception occured in driver: SQLSTATE[HY000] [2002] No such file or directory in /var/www/nextcloud/lib/private/DB/Connection.php:64\nStack trace:\n#0 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(429): OC\\DB\\Connection->connect()\n#1 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(389): Doctrine\\DBAL\\Connection->getDatabasePlatformVersion()\n#2 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(328): Doctrine\\DBAL\\Connection->detectDatabasePlatform()\n#3 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(623): Doctrine\\DBAL\\Connection->getDatabasePlatform()\n#4 /var/www/nextcloud/lib/private/DB/Connection.php(151): Doctrine\\DBAL\\Connection->setTransactionIsolation(2)\n#5 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DriverManager.php(172): OC\\DB\\Connection->__construct(Array, Object(Doctrine\\DBAL\\Driver\\PDOMySql\\Driver), Obj in /var/www/nextcloud/lib/private/DB/Connection.php on line 64
[Thu Jun 21 08:40:56.265763 2018] [:error] [pid 20040] [client 24.64.241.226:42512] PHP Fatal error:  Uncaught Doctrine\\DBAL\\DBALException: Failed to connect to the database: An exception occured in driver: SQLSTATE[HY000] [2002] No such file or directory in /var/www/nextcloud/lib/private/DB/Connection.php:64\nStack trace:\n#0 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(429): OC\\DB\\Connection->connect()\n#1 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(389): Doctrine\\DBAL\\Connection->getDatabasePlatformVersion()\n#2 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(328): Doctrine\\DBAL\\Connection->detectDatabasePlatform()\n#3 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(623): Doctrine\\DBAL\\Connection->getDatabasePlatform()\n#4 /var/www/nextcloud/lib/private/DB/Connection.php(151): Doctrine\\DBAL\\Connection->setTransactionIsolation(2)\n#5 /var/www/nextcloud/3rdparty/doctrine/dbal/lib/Doctrine/DBAL/DriverManager.php(172): OC\\DB\\Connection->__construct(Array, Object(Doctrine\\DBAL\\Driver\\PDOMySql\\Driver), Obj in /var/www/nextcloud/lib/private/DB/Connection.php on line 64
[Thu Jun 21 08:55:09.173195 2018] [mpm_prefork:notice] [pid 1597] AH00169: caught SIGTERM, shutting down
[Thu Jun 21 08:55:18.903741 2018] [mpm_prefork:notice] [pid 1585] AH00163: Apache/2.4.18 (Ubuntu) OpenSSL/1.0.2g configured -- resuming normal operations
[Thu Jun 21 08:55:18.908487 2018] [core:notice] [pid 1585] AH00094: Command line: '/usr/sbin/apache2'