Database Maintenance task finished. 3CX stops working.

[dylanc]

On Sunday morning at 2AM our Database Maintenance task finished.
The scheduled backup that occurs at midnight failed, sending me the following email:

3CX Phone System tried to backup but failed due to the following reason(s):
System.Collections.Generic.KeyNotFoundException: The given key 'INST_ERPEXTERNALFQDN' was not present in the dictionary.
at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
at _3cxBackupRestoreImpl.LicenseUtils.CreateLicenseInformation(PhoneSystem ps)
at _3cxBackupRestoreImpl.BackupRestoreUtils.CreateBackup(String instanceId, String cfgPath, String dbConnectionString, BackupConfig options)
at _3cxBackupRestoreImpl.BackupRestoreUtils.Backup(IFilesystem filesystem, String instanceId, String cfgPath, String dbConnectionString, BackupConfig options, String fullpathFilename, Boolean sendEmail)
at BackupRestoreSchedule.BackupJob.Execute(IJobExecutionContext context)

I tried to log in and my cookie allowed me access to the interface, but when I tried to change anything at all it gave me a "Read only filesystem" error.
The Database Service was marked as stopped.
Some calls were working, but not all.
Rebooting the VM resolved the issue.

I had a similar situation last Sunday as well, but not earlier than that.
I noticed that my auto-update was scheduled for 2AM Sundays, sos I've changed the automatic updates to 4AM Sunday to get them clear of the database maintenance if it isn't triggered by the auto-update itself.
3CX Version: 16.0.1581
The VM is the 3CX Debian install from 15.5. Currently Debian 9.1

Any ideas as to what's going on here?

 

[cobaltit]

Does this PBX have the instance manager access enabled?

 

[dylanc]

No, we haven't enabled it as yet