The 406 error indicates that you are being blocked from accessing uTest, likely due to incorrectly entering your password too many times. The solution is to wait at least 24 hours before re-attempting to login to uTest. Failing to wait 24 hours before re-attempting will only continue/extend your lockout period.

This error is often (but not always) related to use of the uTest proxy. Please note that if you are resetting your uTest password while using the uTest proxy, you MUST first disconnect from the uTest proxy on all browsers/systems/devices, and then set them all up with the new credentials. This may mean closing your browser and removing all browser data (cookies, etc.). Please make note of the following:

• When you reset your password, you will be automatically logged in and should not log out for at least 15 minutes. You also should not attempt to access the proxy in that 15-minute window or else you will be locked out for an hour. 
• When you are locked out of your account temporarily, the error message says “invalid username or password” which logically leads you to try again, and adds another hour to your lockout time. 
• After 10 failed login attempts, you will receive the 406 error and your IP address will be blocked for 24 hours. Please avoid continuing to enter your password to prevent extending your lockout time.
• The proxy will attempt to authenticate multiple times per second. Mistyping your proxy password just once and navigating to a web page while receiving a few notifications on your device can be sufficient to reach the 24-hour lockout limit.

The issues you are encountering are not caused by the proxy. However, since proxy setup is when we're most prone to mistyping our password, it increases the likelihood of triggering the lockout issues.