Text Message "Not sent. Tap to try Again" with Moto G

I have recently converted from Verizon to T-mobile with my Moto G power 5G- 2023. 

I was using this device for an year and never had such issue with Verizon. 

I found the pattern.

There is no problem while a call is being made on this phone or for a few minutes after the call ends. However, after that, any text message is not sent from my phone while I am still able to make/receive any call or receiving any test message. if I make a call to anyone and re-try to send it, it works again. 

Not I have unlimited text/voice call in US. But when I am overseas with the roaming service, voice call will be in extra charge with. my plan. so that will be in trouble for me.