Thunderbird-Hilfeforum

I set up thunderbird email account on my computer and my iphone. I can only send and not receive emails on my computer account and I can only receive and not send from my phone account. When I try to send emails from my phone the email bounces to my outbox where it sits and I get a message that says "Cannot Send Mail The sender address was invalid" I think something was off in the initial setup because this problem has persisted from the beginning however I cannot figure out how to fix it. Need help please so that email sends and receives from either location: computer or iphone.