Nextcloud version (eg, 20.0.5): 28.0.4
Operating system and version (eg, Ubuntu 20.04): Ubuntu 22.04.03
Apache or nginx version (eg, Apache 2.4.25): nginx/1.24.0
PHP version (eg, 7.4): 8.1.2
The issue you are facing:
Is this the first time you’ve seen this error? (Y/N): Y
Steps to replicate it:
sudo -u www-data /usr/bin/php /srv/www/cloud.frelia.org/cron.php
PHP Fatal error: Cannot declare class OC\Command\CommandJob, because the name is already in use in /srv/www/cloud.frelia.org/lib/private/Command/CommandJob.php on line 3
Nextcloud instance itself works normally but complains about last background job execution running 7 months (what?!) ago.
I’m running cron.php as a systemd service:
[Unit]
Description=Nextcloud cron.php job
[Service]
User=www-data
ExecCondition=/usr/bin/php -f /srv/www/cloud.frelia.org/occ status -e
ExecStart=/usr/bin/php -f /srv/www/cloud.frelia.org/cron.php
KillMode=process
The first time I can see the error in journalctl -u nextcloud-cron.service is 2024-03-20
UPDATE @ 02:44
In my nextcloud.log I could find the following entry:
{
"reqId": "f3vl9SsZAHTLOuSpiQJl",
"level": 3,
"time": "2023-08-17T15:08:30+00:00",
"remoteAddr": "",
"user": "--",
"app": "PHP",
"method": "",
"url": "--",
"message": "Cannot declare class OC\\Command\\CommandJob, because the name is already in use at /srv/www/cloud.frelia.org/lib/private/Command/CommandJob.php#31",
"userAgent": "--",
"version": "27.0.1.2",
"data": {
"app": "PHP"
}
}
So I had this problem since at least 27.0.1.2 
UPDATE @ 04:11
I give up. So far I tried:
- Upgrading to PHP 8.2
- Upgrading to PHP 8.3
- Simply rebooting
- Restarting Redis
- Restarting PostgreSQL
- Restarting PHP-FPM
Result of occ integrity:check-core -vvv
$ sudo -u www-data /usr/bin/php8.3 occ integrity:check-core -vvv
No errors found
Result of occ setupchecks
$ sudo -u www-data /usr/bin/php8.3 occ setupchecks
dav:
✓ DAV system address book: No outstanding DAV system address book sync.
system:
⚠ Errors in the log: 2068 errors in the logs since March 22, 2024
ℹ Brute-force Throttle: Your remote address could not be determined.
✓ Cron errors: The last cron job ran without errors.
✗ Cron last run: Last background job execution ran 7 months ago. Something seems wrong. Check the background job settings.
✓ File locking
✓ Maintenance window start: Maintenance window to execute heavy background jobs is between 1:00 UTC and 7:00 UTC
✓ Memcache: Configured
✓ PHP modules
✓ Architecture: 64-bit
notifications:
✓ Push notifications - Fair use policy
security:
✓ App directories owner: App directories have the correct owner "www-data"
✓ Old user imported certificates
✓ Code integrity: No altered files
ℹ Forwarded for headers: Your remote address could not be determined.
✓ Old server-side-encryption: Disabled
✓ PHP version: You are currently running PHP 8.3.4.
✓ Random generator: Secure
database:
✓ Database missing columns: None
✓ Database missing indices: None
✓ Database missing primary keys: None
✓ Database pending bigint migrations: None
✓ Database version: 12.18 (Ubuntu 12.18-1.pgdg22.04+1)
✓ Database transaction isolation level: Read committed
config:
✓ Default phone region: PL
✓ Email test: Email test was successfully sent
✓ Overwrite cli URL: The "overwrite.cli.url" option in your config.php is set to "https://cloud.mydomain.org" which is a correct URL. Suggested URL is "https://localhost".
✓ Configuration file access rights: Nextcloud configuration file is writable
network:
✓ Internet connectivity
✓ JavaScript modules support
php:
✓ PHP default charset: UTF-8
✓ Freetype: Supported
✓ PHP getenv
✓ PHP memory limit: ?
✓ PHP opcache: Correctly configured
✓ PHP "output_buffering" option: Disabled
✓ PHP Imagick module