I created a google-group
mygroup and asked to also create an email address for the group,
email@example.com. I want to email from my gmail account such that the sender address will be
I went to Settings -> Accounts and Import -> Send mail as: -> Add another email address, added
firstname.lastname@example.org, checked "Treat as an alias" and clicked Next, but got a red error message saying "Please enter a valid email address".
How can I add this sender address?