USSD Not working on modem anymore

[Japster]

Last night while I was browsing for some reason my modem dropped my connection, the signal was fine, but it just disconnected. I tried the whole evening with different modems, but I could not make a connection with the modems, using my MTN sim.

Now for some reason this morning I can connect to the internet again, but I cannot access the USSD commands on the modem. I just keep on getting "Your request failed, please try again later.". Does anyone know how to fix this?

 

[Japster]

I also for some reason cannot receive any sms's on this sim.