How can I or a candidate change the email address, after they have joined a candidate portal?

How can I or a candidate change the email address, after they have joined a candidate portal?

I have been testing with + plus addresses for having a vendor manage multiple candidate profiles (I've posted another question on this: https://help.zoho.com/portal/en/community/topic/how-can-i-have-a-vendor-work-on-the-candidates-profile-fields)

After having invited the candidate to the portal (which is me testing), and logged in, I noticed that the email address cannot be changed by the candidate. Then I went over to the profile (as a Zoho Recruit admin) and was not able to do either. The error message basically stated, that the email address cannot be changed, because the candidate is in the portal. Then I deactivated the login of the candidate, by clicking on the menu. Same problem.

Any ideas?

Thanks!