Not receiving submissions via Email

Everything has been working fine then one day the email notification said "undefined". Support said the information was blank. Thete were no fields in the email notification settings. So i fixed. Tested. Everything fine. Now today the forms wont email to me. 

As far as I can see, the messages are being sent.

However, since you have switched the Sender email from default one, the sending source has been switched too. In order to test the new sending method, please submit your form.

If you need any further assistance on this, please let us know.