Hi @Markus Knödler Welcome to the Atlassian community.
Can you give me more details about the error like where did you getting this error as these errors are mostly get while loading the boards also looking at the provided deployment details you mentioned your deployment type as Cloud and Product Plan as Premium but looking at the stack trace your Jira URL looks like a self hosted platform https://dna.emag.com/
These are mostly related to due to some third party plugin issue or javascript configured in the Jira announcement banner.
Please try removing the announcement banner if any and confirm that solve the issue if not then reproducible on the lower instances and run the Jira in in safe mode (disable on third-party plugin) and enable them one by one to find out the one which causing this issue.
Please check the below documents for more details which are having similar issue.
https://confluence.atlassian.com/jirakb/is-not-a-function-error-thrown-by-browser-779158969.html
Thanks
Ravina
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.