The comment is right, you need to have a SMTP that allows this. An own domain is a starting point, that would give you much more options (it's by the way also f*** cool, best thing to do!)
Also, providers like G-Mail limit the number of accesses to the services. (EDIT: sending and receiving -> 1 service contact in 15 min.)
For testing you should use H-Mail server
] locally on your machine.
You would have unlimitedd access there. P
lease be aware that it has a auto-ban option too (can be switched off).