Mac Sierra - Mail app crash when composing and adding addresses

My Mac Mail app always crashes very consistently when I am composing an email message and try to add an alias to the sender fields. It happens on adding one particular alias only. For others it works. So far I have just searched the forums and have not found anything that is close to this issue.

Below is my Mac spec.

MacBookPro14,1

Processor Name: Intel Core i5

Processor Speed: 2.3 GHz

Number of Processors: 1

Total Number of Cores: 2

Memory: 16 GB

System Version: macOS 10.12.6 (16G1212)

Kernel Version: Darwin 16.7.0

Thanks,

Shreeni