@Joseph-TP 

I have the same issue with a DECO X10-4G which is annoying since I used an older TP-Link M7350 mobile internet pocket router without any problem.

I kindly ask TP_Link support to quickly handle the issue, since the current bug makes me impossible to use their new products and so I (and problably other MultiSIM users as well) will have to bring back the routers to the wholesaller.

I have to emphasze that this MultiSIM offering is very populer here and will probably take over single cards since the network providers are using it as a tool to bring all the mobile internet contracts to a single provider...

Looking forward to hearing about the solution (which might be easy, since it is still workoing proerly on older tp-link devices).

  @ggaszton good news that TP-Link prepared a new firmware which works fine on my device, I mean it doesn't refuse the incoming call on the Multi-SIM. I suggest you to raise a support case with TP-Link support.

  @Attila81 Hi, I have exactly the same problem. As far as I know, the firmware of my router is up to date, but the issue is still a thing. Would you be so kind to give me a detailed instruction how to solve it? Thanks in advance!

  @Attila81 Is it possible to share with me the FW? Or could the support get in touch with me? I have the same router and the same problem, and I cannot use the router at all :(

Many thanks!!!

  @Routerfly78 I can share it with you but I am not sure if that's fully compatible with your device version. So compare it with mine I wrote to the ticket.

That's the download link I got from TP-Link support: https://tpbeta.com/s/x8B7HJePrCPKyNB/download

Good luck!

  @molnarm sorry I just noticed your post.. So I received a beta firmware from TP-Link support. But be carefull since I am not aware of your exact hardware version and I am not sure if it is compatible with your device. However you can download it from here: https://tpbeta.com/s/x8B7HJePrCPKyNB/download

Hello all, Tp-Link moderators,

I have the exact same issue with a fresh purchased TP-Link MR550 LTE router bought on Amazon.

This is also a "Multisim" card, and if the MR550 is connected to the LTE network, it rejects incoming calls which also makes my phone with the "main" SIM card do not ring anymore. I just see a "missed call" notification.

I see there seems to be a beta firmware for some models.

Would it be possible to share a new firmware for the MR550 users?

Should I create a new thread in this subforum for it?

For better understanding what "Multisim" is for:
It allows you to have a kind of copy from your main SIM card and using the same contract/data plan. So you do not need to purchase another data/LTE subscription and use with up to 5 SIM cards the same contract. All SIM cards do ring if a call comes in, and the device that picks up will have that call. So if the TP-Link router rejects by (firmware) design a call because it has no call functionality, it also rejects the call for all devices, which makes the Multisim unusable. Some devices from other vendors let you configure how to react if a call comes in. This would be of course the best solution. But just to ignore the call will also work. Multisim is a featue from all main phone providers and very common in Europe.

Thx!