Hi Lakishia Powell,
If you are a beginner or novice an error like this may be distracting but easy to be solved once you check your own practice and data.
The <<email-address>> TAG may have a slightly different name in your setup but refers to the column where FormMule is going to obtain the actual email-address to send it to.
This must conform to the 'iden...@domain.toplevel' markup and the best practice is to checkmwtch this at the form question to avoid collecting bogus addresses.
Enrichments like:
"Firstname Lastname" <iden...@domain.toplevel>
may work yet can fail over time...
...all due to a mailserver which can reject the address and returns nothing more than this Error: Invalid Email:
An expert would verify whatever you pushed after To: for an address and check if this conforms with the convention and if it ain't you get the same error.
FM doesn't care if the entered address exists or is vlank or not, it'll push the mail to the SMTP server and if that rejects this then your (double) checks are to be improved to ensure it's correct and SMTP acceptable.