[Xiaomi Mi 11] iamrance.asa:
Yeah, it seems like it's an carrier issue if it is just the one carrier and they use the same bands. Maybe an APN setting or they could be blocking it on their end. You will need to contact them about it since it's a band that works on it with other carriers.

Ah, I see that SafetyNet is indeed failing on your device via CTS Profile. So let's fix this with Magisk since it has to be a unlocked bootloader issue.

Installing Magisk:

Method 1: (with fastboot and firmware)

**Make sure you have the firmware for the exact firmware your on (i.e. MIUI 12.0.13 have MIUI 12.0.13, MIUI 12.5.1.0 have 12.5.1.0 -- and with the same regional rom identifier)**

Extract firmware zip and copy the boot.img onto your phone's storage

adb push [drag the boot.img into terminal here] /sdcard

Install Magisk APK

adb install [drag downloaded Magisk APK here]

Open Magisk on phone, click install, then click "Select and Patch a File"

Select the boot.img pushed in step 1 then "Let's Go"

It should patch the boot.img and give you a link to the patched one

adb pull /sdcard/download/magisk_patched-23000_xxxxx.img [location on computer you want it]

Type "adb reboot bootloader"

Type "fastboot boot [pull patched boot.img for location you picked in step 4]"

Enter. (Phone should now boot)

If things go correctly, you should now have a temporary root. Go to Magisk>Install>Direct Install>Let's Go

If it happens to bootloop, you can just hold down the power and volume buttons and let it restart. It will use the original unaltered boot.

Now you have it permanently installed

Method 2: (TWRP and Magisk.zip)(No custom recovery install)

Download TWRP for Mi 11 and Magisk zip (from the Magisk APK)

Should have the option in Magisk App>Install to download the zip (leave zip in phone storage)

Type "adb reboot bootloader"

Type "fastboot boot [drag TWRP.img from step 1 here]" and Enter

This won't install it since it's the fastboot boot command

It should boot into TWRP

If it asks for a password, it's your pinlock for your phone. If pin doesn't work, restart the phone and turn screen lock off (this is a bug in TWRP)

Accept the allow TWRP to modify device, etc stuff

Click the "install" option then find the Magisk.zip that was downloaded and flash it.

**MAKE SURE TO UNCHECK ANYTHING ASKING YOU TO INSTALL TWRP! Check Advanced Tab and Settings Tab and after choosing to reboot, make sure not to accept install TWRP if it asks! **

If successful Magisk should be install. You can reboot the phone now.

Magisk Setup/Fixing SafetyNet:

Go to Magisk>Settings (Gear icon)

Hide the Magisk Manager package and Enable MagiskHide then back out of settings

Click on Shield Icon>MagiskHide

Click the box for all Google apps, banking apps, streaming services, and any app that you think won't get along with knowing you have root

Download Universal SafetyNet Fix from @kdrag0n

Click on the Puzzle piece at the bottom of Magisk Manager's home page

Search for "MagiskHide Props Config" and the download icon/install

Don't reboot. Go back to the Puzzle piece page.

Click on "Install from storage" at the top of this tab and install the Universal SafetyNet Fix zip we downloaded.

Reboot

Check SafetyNet, it should pass now. Cheers