@Akarv 

Follow this guide for troubleshooting your issue.

If that still doesn't work you can use the MR200 remote management:

Go to Advanced > System Tools > Administration page. Locate the Remote Management section.

If you still can't remotely access your MR200, the possible reason for that could be a CG-NAT used by your ISP.

Check your Internet IP address here:

If this IP address is private or in the range 100.64.0.0 to 100.127.255.255, then that's the reason for this behavior.

  @Akarv 

Make sure that you're with the latest FW release for MR200 HW v4, which is v1.19.0.0.9.1.

This setting should suffice, but the bad news is that you can't use the Remote Management, because you're behind a double NAT from your ISP.

If your Internet IP address is starting with 10.x.y.z, it means you receive a private IP address, and the Remote Access feature won't work, unless you have a public IP address.

At this point you can contact your ISP and ask if there's an option, you could get a public IP address assigned to your MR200.

  @Akarv 

Hi, the remote management function you've configured is for web management page, however, like @terziys said, since the 4G internet IP address assigned by your ISP is a private IP address, the remote web management will not work until you obtains a public IP address.

In addition, for Tether App, if your device supports TP-Link cloud function, you will be able to bind the device to a TP-Link ID and manage it via Tether App remotely, however, upon checking, MR200 V4 doesn't support TP-Link cloud function, thus it can only be managed locally via Tether App.