I am testing a new application and users are getting a 403 Access Denied Error when interacting with task links from email, but are otherwise able to access the task via tempo or the application's site. The users are already logged in.
Any idea what is causing this?
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Whenever I've had "403 - Access Denied" it's always been down to security or user permission issues. Have you tried testing this with a system administrator account and seeing if the issue still persists?
That is what I suspected at first as well, but users being able to access the task via Tempo/sites, but not task emails is not something that I've seen before.
I tested it with a system admin account and do not have any issues.
The fact it works with a system admin account but not with basic users reinforces to me it might be down to security, but like you said it seems odd that they can access it via other methods. Justin's suggestion below seems plausible, based on the documentation they linked.
Edit: Have you checked the tomcat-stdOut logs (inside System Logs) around the time when the user got the error? It might shed some light on the issue.