JEM permission migration is incomplete

Hello,
I've migrated my joomla instance from version 5 to version 6.
After that I migrated to the newes JEM version.
Unfortunately since migration no events will be show in frontend. In backend editing of existing events is not possible. 
In the JEM dashboard following information is shown:
"JEM permission migration is incomplete. Event, category and venue changes are temporarily disabled. Settings remain available. An administrator can continue the migration from the JEM Control Panel. The Joomla ACL hierarchy is inconsistent. No automatic global rebuild was attempted.".
I've assigned my user to the JEM admins group, but nothing changed. What should I do?
Best regards
Thomas
 

Which JEM version were you using before, and which version are you using now?
Have you tested JEM 5.0.2 RC1?
Donwload from: www.joomlaeventmanager.net/download/beta-versions

I've installes pkg_jem_v5.1.0beta5 which I've downloaded from that link.
I've used before Joomla 5 and migrated to Joomla 6. As I can see all events etc are available, but they will not be shown in frontend and in backend I have no edit rights..
Kind regards
Thomas

Which JEM version were you using before?
You've now installed JEM 5.1.0 Beta 5 on Joomla 6, right?

Before I had JEM 4.5.0 installed.

Do you test refresh JEM 5.1.0 beta 5 with new Diagnostic tool?
Download from:
www.joomlaeventmanager.net/download/beta-versions
Reinstall it and run Diagnostics, and tell me if you see any error or if you have any JEM override.

How to run JEM Diagnostics

1. Sign in to the Joomla administrator area and open JEM → Housekeeping → Diagnostics.
2. Click Run checks. JEM checks the full configuration; you do not need to select an event, menu, or user. The audit is read-only and saves a dated report with its own ID.
3. Review Verification rules for frontend visibility, then Checks and actions for warnings, errors, recommendations, and links to the relevant settings. Context means a filter or override may need manual review; it is not an error by itself.
4. Review the inventory, modules, plugins, menu views, languages, and overrides to understand the site configuration.
5. If you need help, use Download report or add observations, confirm the email consent, and click Send to JEM. Selected settings are exported with sensitive values redacted. You can reopen the result later under Recent diagnostic reports.

More info: Improve JEM Housekeeping with three tools