What is the difference between Connect external address and Connect other when adding a new support address?

Question

What is the difference between Connect external address and Connect other when connecting a new support address? 

Answer

Connect other is used when Connect external address fails. This can occur when attempting to connect support addresses that are considered unsupported like Google groups and distribution lists. Use Connect other with caution.

For more information on using these types of support addresses, see the article: Can I use an email alias, distribution list, or Google Group as a support address?