RUTC50 Modem issue since Update - Mobile 5GMM reject cause: N1 mode not allowed

Networking Solutions Issue
23

Hi…

Here… The C50 only do Internet, through LTE 5G. I am using it at my workspace… and this the only internet I have, here.

24

Hello,

I hope you are doing well.

Our R&D team has developed a beta version of the modem firmware, and we are currently looking for users who are still experiencing this issue to test the firmware and verify whether it resolves the problem.

If you are willing to participate, we can arrange a remote session with our R&D team to install the firmware and investigate the issue further.

Please let me know if you would be available for such a session.

Kind regards,
V.

1 Like
25

Was there any volunteer who tested the beta modem firmware already ?

Best,
Christian

1 Like
26

For your information…

the problem seems to be location-dependent.

I was traveling with the router for two weeks (Germany, Austria etc.) and had no 5G problems. Now I’m back… and the problems at this location/cell tower are back. :frowning:

27

Hello,

I am still arranging remote sessions with the users, if you would like to participate, please let me know.

Kind regards,
V.

28

Hi, same issue here.

29

Hello,

For troubleshooting purposes, we will require more sensitive information from your end, such as the troubleshoot file, which may contain passwords, public IP addresses, serial numbers, and such. To avoid leaking this information, we have sent you a form to fill out, which you will receive in your e-mail inbox that you have registered your account with in the forums. In the Ticket ID field of the form, please enter the ID of this thread, which is 18440-4.

Please let me know once you filled out the form.

Thank you,
V.

30

I am available this week and we can schedule a remote session for troubleshooting and beta modem firmware tests.

Best,
Christian

31

This update fixed the problem for me for about two weeks, but as of today the 5G problem has returned. No other changes to the system.

32

I found this thread searching for “5GMM reject cause: N1 mode not allowed”.

We have a RUTM30 on O2 network in Northern Ireland giving the same error and the same problems the modem endlessly resetting. In 4g mode the unit operates ok but it can be a struggle to get it to switch back.

Unit: RUTM30
Modem Firmware: RG520NEBDCR03A05M4G
System Firmware: RUTM_R_00.07.22.1
Installed 31st of March 2026.