router os error+port 20561 timed out!

Hi there
I have a router SXT.while i configuring it with winbox, when i added port at Bridge -->ports tab the winbox kicks me out at router and i can’t get in neither MAC address or IP.it’s keep showing me the error port(20561). I have tried different version of winbox an nothing worked.i don’t have access reset the router to factory defaults
would anyone please help me?