I can't send invoice keeps saying check customer email address

Hi aza76 Is the email address a valid email and are you able to send the invoice to yourself as a test to see if you're able to send/receive it?

Hi yes I can send invoice to myself but not customer its keeps saying check email address is correct which it is?

Hello Aza76, can you take the email address out of the customer info section and save it then re-add it in again and save it and try send your customer the invoice and see if the same thing again or not.