Although Yahoo mail is considered to be one of the most reliable email service providers, there are times when users encounter problems while working with it. If you face issue while receiving Yahoo verification code, you can refer to the following guide to fix this problem:
Check the mobile phone number twice.
Provide alternate phone number and email address
Click on the option of resending the verification code
Now, enter the correct code in the required field

These are some basic troubleshooting steps you can follow to fix this issue of Yahoo mail not sending verification code. If you still encounter the problem, contact Yahoo customer service number and speak to a well-trained expert. https://www.email-helps.com/yahoo-support/