Gain login access to MxU.
As soon as you sign up for MxU, or are invited to an existing team, you'll receive an email with instructions to activate your account within a few minutes. Sometimes these end up in spam or junk folders, so make sure to check there too.
If you were invited to an existing team, it doesn't hurt to double-check with the Owner and make sure they sent your invitation to the right email address. If they made a mistake, then can send a new invitation to your correct address.
If you just signed up with a team invitation link and are waiting for a confirmation link to be emailed to you, the same advice applies: make sure to check your spam and junk folders after a few minutes.
If all else fails, you can always reach out to support for assistance with logging in.