Users cannot log their time against a task

[Mitch Alves]

Many users start suffering in issue now, note error screenshot:

JIRA_Log_Error.png

Note we have JIRA for years now and no admins have made any modifications.

Can someone assist?

[QuentinB]

Hello, You can maybe check if this is an error due to add-on installed: Turn on safe mode in toJIRA Administration > Add-ons > Manage Add-ons > Turn on Safe Mode check if any add-ons that are causing this. Retest.
If not I suggest you to open a support request: https://support.atlassian.com/help/