This happened to me (February, 2021). It never happened to me before with Google Groups I created/moderated.
I am starting to suspect a pattern: I think that people with a university address tend to not get properly signed up -- even from universities that use Google for their email!
The workaround I found is to have the person send an email to sign up for the group. Let's say your group is called Kim-Friends. The person should log into their personal gmail account, not their university account, and send an email to
email@example.com. When I tried it out I put the word
join in the subject line and in the body of the email but my guess is, that's not necessary.
They should get an automated response something like this:
We received your request to join kim-friends.
kim-friends requires owner approval for join requests. If you would
like to continue with your join request, reply to this email or click
In my testing, clicking below, on the big blue button, did not work. Replying to the email did work.
As a final step, the owner or manager will need to log in and approve the new member(s).
Note that the person should be able to set up an automatic forward which will enable them to read group messages from their university account.