Hello @mara.mossberg
What is the URL that the user is using?
Can you share that with us? You can eliminate the base URL.
Example:
https://----.atlassian.net/jira/software/projects/TKA/boards/2
Can other users use the same URL successfully?
Does the person experiencing the problem actually have permissions within the referenced project to see the project? Just because a user has administrator privileges does not mean they have access to a project. You didn't say what type of admin the user is. The could be a Project Admin, a Jira Product Admin, a Site Admin, an Org Admin, .... Not all of those give the user access to see the project or its content.
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