@JL3938 

Good day.

Thank you very much for your time and patience.

How long have you had the modem and is it getting a better signal before?

Have you ever put the sim card into the mobile phone to test the speed, also the APN information to see if the 4g router used the same information on the phone?

https://www.lifewire.com/how-to-change-apn-settings-on-your-mobile-device-2377931

Please also try to relocate the modem to some higher and more open space without barriers;

And always keep the modem on the latest firmware: Archer MR400(EU)_V1_181112

https://static.tp-link.com/2019/201901/20190103/Archer%20MR400(EU)_V1_181112.zip 

Thank you!