No outbound messages with Twilio text messaging service - Twilio Error code: 11200

I carefully followed the instructions for Twilio (Text Messaging ) and been successful till the last step of successful deployment on gcloud. I also have the URL being generated by executing gcloud run command and pasted it in Twilio "When a message comes in" field.

Now when I send a message to my active Twilio number on which sms services are being enabled, I only receive incoming messages which I can see in Twilio logs but no outgoing messages. In fact I receive an error code on Twilio: 11200 which is timeout error and nothing of google cloud logs other than successful deployment.


Below is the snippet of successful deployment.


Does anyone knows what's going on or what I am doing wrong? I followed the instructions multiple times though.