I guess mine is a different situation. I too get an error (“An error occured during the request. Unable to proceed.”) when trying to display the user list. However in my case the log says “TypeError: Argument 1 passed to OCA\Provisioning_API\Controller\AUserData::getUserData() must be of the type string, integer given, called in /…/nextcloud/apps/provisioning_api/lib/Controller/GroupsController.php on line 209 at /…/nextcloud/apps/provisioning_api/lib/Controller/AUserData.php#81”
Some of our users have a number, an ID, as loginname. If a group doesn’t have a member whose loginname is a number, then the user list displays perfectly well, otherwise it doesn’t display at all, ginving the error mentioned above…
Users with a “number” account have no problem logging in. We can still share files and folders with those accounts and creating new shares with them still works. It’s only the user list that doesn’t work.
We use Nextcloud 14.0.0, upgraded version 13.0.6 after switching to “beta” channel. We had no problems with “number” accounts in previous versions (starting with Nextcloud 10).
Total of 31 users of which 5 use a number as loginname.