Please follow the steps below if you do not receive a code when verifying or changing your Gmail account password through Gmail:
1. First, check the internet connectivity, is it working properly
2. Then, you can try clear your browser cookies and history
3. Your browser should be up-to-date
3. Business or government email might be the reason.
Read more: https://ityug247.com/not-receiving-google-verification-code-text/