I have tried to create a Mastodon account on my iPhone. I have followed the guidelines to create a username, but have received indications that it does not need the format requirements. Also, when I enter a password, I receive a message that password must be at least six characters. Even if I choose strong password, I still receive the message that it must have six characters. Does anyone have suggestions on the appropriate format to create a username? I am using the app sign followed by my name followed by @mastodon.social. Thanks.