Hello,
I have a problem of access vy URL on Nextcloud.
I obtain an error 500.
This problem arrives just after an update of Php on my NAS Synology (Nextcloud is installedon my NAS).
On errorlog I can see this message:
Failed to connect to the database: An exception occured in driver: could not find driver in
I do not understand where from it can come.
Check if your database ia running and you have the right php connector module installed and up.
Provide some more information about php and database version and check for errors in database and webserver log.
database is running…
on my NAS I have php5.6 and php7.0 installed…
database installed is MariaDB5 and MariaDB10… I use MariaDB5…
in webserverlog I just can see this:
Failed to connect to the database: An exception occured in driver: could not find driver in…
Could you verify that the pdo_mysql php module is active for the php version used by nextcloud? You could verify by creating
nano /path/to/nextcloud/phpinfo.php: <?php phpinfo(); ?>
inside your nextcloud folder and open it in browser. pdo_mysql module should be listed there with related settings etc.
No idea how multiple php versions AND multiple databases are handled well on one system, but I guess the php update messed something up on which php is accessing (with which connector module) to which database.
I have no informations about pdo_mysql… 
I have modified php configuration on my NAS with “web station” to add “pdo_mysql”…
Now I can see informations for pdo_mysql…
But always “error 500”…
In webserverlog I can see now
Failed to connect to the database: An exception occured in driver: SQLSTATE[HY000] [1045] Access denied for user ‘adm_cloud’@‘localhost’
But when I check nextcloud database privileges with phpmyadmin I see that:
It’s OK…
I have deleted user et recreated it…
It work now !!!
Thank’s.