One of our users gets regularly the following error message:

"A problem accured
refresh the page or navigate to another page. If you continue to see this message, there may be a problem with our service
Error: X4Y9RS"
We have this problem only in one project and with only one single user. All other users who work in this project, do not receive this error.
Its an personal project, the user has a Jira software licence and admin rights for this project.