Could it be that your provider is blocking some ports required by RMS? A complete list for RMS services is provided here.
Could you login via SSH into your device and post the output of the following commands:
- telnet 126.96.36.199 15009
- telnet 188.8.131.52 150010
Are you in some private network, while using these SIM cards?
I would also like you to attach a troubleshoot file to your question. Please, replicate the issue, then access router's WebUI, go to System -> Administration -> Troubleshoot section and download troubleshoot file from there.