File Access Error after Update 21.0.1

Hey everyone,

after updating our Nextcloud-Instanz from 20.0.9 to 21.0.1/21.0.2 some of our users cant access there files anymore.
When i check our OnlyOffice-Log there are 403 - Access denied errer.

Jun 14 08:23:05 [2021-06-14T06:23:05.663] [ERROR] nodeJS - error downloadFile:url=https://xxxxxx/apps/onlyoffice/download?doc=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJhY3Rpb24iOiJkb3dubG9hZCIsImZpbGVJZCI6MjU2MTM4LCJ1c2VySWQiOiJhLWIubXVzdGVybWFubiJ9.Qs_wgCiafUKJGTWjltBRA0WDcGWh3a0h9whvFNM0K-c;attempt=3;code:null;connect:null;(id=1408696974)

Jun 14 08:23:05 Error: Error response: statusCode:403 ;body:

Does anyone got the same error after update or does anyone knows how to fix it?
Thanks for your help!