Miner name must be alphanumeric

HOST: hub.miningpoolhub.com
PORT: 20575
Username: weblogin.workername

thats how username should look like so for me it would be "Airy.1" BUT I CANT EVEN NAME HIM "Airy1" caused miner name must be alphanumeric or "filed attempt to change". Im so much tilted, pls tell me how to fix it, cant think clearly