I have a serious problem with my archer mr600 v1, since the off or removed the sim , then i put sim back on and on , does not want to know to connect to the network 

the problem is that does no connetc to the 4g network , i tried with the network 3g, if put 4g preferred does not go the 4g , if put 4g fixed i go in 4g+ but does not connect , as reboot the router returns the low network , does not want to know to go in 4g , I would like to know if someone can help me , thanks