Canon printer won't connect to TMobile wifi router

Your problem is pretty common among T-Mobile Internet users. This usually fixes the problem.

Try adding a new WiFi network for the Canon(s). Use the T-Mobile app and tap the Network tab on the bottom, then the "+" button on the lower right. Create a new 2.4 GHz WiFi network with a unique name (SSID), just for your printer. Make sure the WPA type is WPA/WPA2. This is different from your main network which, by default, is WPA2/WPA3.

Now, go to your printer and clear out all of the information you have entered for your printer's setup and then recreate your wireless connection to the new network you just created. I'll bet you'll be good to go.

¡Buena suerte!