Common things to look for when seeing errors or not able to connect to a Master Server.
Make sure you are not using Master 3101 - This is being decommission, choose any other USA Master Server.
Verify your Repeater Call Sign is listed first followed by any details such as site name or location. Example W1AW - 1 or W1AW/R or W1AW ARRL HQ.
Verify your Repeater Call Sign and 6-Digit ID is the same as registered with RadioID.net. You may change the call sign at RadioID if not correct or on the Repeater in the Call Sign/Radio Alias fields to match.
MMDVM Repeaters must now set a device password in the Sysop Dashboard, see Device Password. This password is then entered into your Repeater either as hotspot security in pi-star or password in MMDVMHost.