Weird, I don't even use hivesigner anymore, too buggy imo. Keychain works flawlessly for me. Anyway, you cannot login to most hive-tube powered sites with a peertube login (to upload your videos etc) unless the owner of that site gives you a channel and login there.
Please contact us if you would like a channel on cast.garden so we can get your desired channel info created on that site. Email agorise@pm.me or in our matrix chat: http://agorise.chat Thanx! :)