Hi Dinç Ekmekçi,
Thanks for posting in the community.
Since you have tested on different computers, the issue is not caused by the devices and browsers. For the error message, I haven’t found any related threads about this feature while it seems something stuck in the backend for the specific accounts. To troubleshoot whether the issue is related with the specific account, I would like to collect more information:
- Please remove the permissions of the two problematic accounts from the site and re-add again, then check whether the issue exists
- Does the issue exists in other libraries or other sites for the two accounts? Also, you could create a new library/site to test.
Regards,
George