Blank pages in Admin

Hi, i have following Problem:
I cant’ access lucee/admin/web.cfm -> plank white page
I can access lucee/admin/server.cfm, but only a few pages works (Output, Request,Tasks Error,…)
Many of the pages doesn’t work: Cache, Datasource, Loggin… -> White Blank Page

this happens after in upgrade Mysql-Extenesion and then downgrade it because Version 8 doesn’t work. After the downgrade the webpages works again, but in the admin, i get blank white pages on the important settings.
What can i do?

Thanks for your help

please always mention the exact lucee version you’re using

Thansk for your answer. I was the latest lucee-version.
I solved the problem: My admin had created wrong users without right permissions.