Just to put my name down here as well. I made another topic, but it seems that this issue has already been discussed in-depth here. We are really struggling with this problem on our mutliple-journal installation: Edit and "login as" users not working - #2 by ajnyga
Here is the post in full:
We are currently on OJS 3.1 and our journal managers cannot edit user accounts (adding roles) and cannot “login as” these users? The are getting the following message:
You do not have sufficient permissions to administer this user. In order to administer a user, you must either be site administrator, or administer all contexts that this user is enrolled in.
Can anyone shed some light on this please?
Regards