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I get this message when I try to add a user as a watcher to an issue:
There was an error adding watcher
How do I fix this? I thought that since I have admin rights, I can do that.
Check the permission scheme for your project. There is a specific permission called 'Manage Watchers' (Ability to manage the watchers of an issue.)
Your user need to have that permission to be able to add/remove watchers.
As @Sana Safai said, there is an specific permission for this.
Even if you are an administrator, if you don't have this permission you won't be able to add/remove watchers.
I attach a screenshot in order to show you which permission are we referencing to:
You should configure these permission as you want to satisfy your needings.