Invitations failed

Hello, with my account Greenhunter, I sent multiple invitations to my friends, but when they accepted it, it said “an error occured” or the message wasnt there but they werent in the tournament. Can anyone help? (i also have many side accounts named Greenhunter2, Greenhunter3, Greenhunter4 , which use the same email and password, dont know if that is a problem) So what is the cause for a not working invitation?

Try logging in from a private window and then send your invitations.

ok thanks