The reason for this is probably because the phone is using the default sip port of 5060. You can correct this by following instruction in this video.
https://www.ringroost.com/faq.php?cat=14&q=195
That phone extension is trying to register with the wrong credentials. Wrong password.
I think it would be best to go to the dashboard and remove the phone and add a new sip phone call control. But those new credentials username and password into the phone.