Email from a specific domain bounces back undeliverable

Hello,

I have been participating with Gallup polls and any time I try to reset my password automatically or redeem any points automatically the emails never come through and I have to take days to get it done manually via support. I asked them to look into it on their end and they said all of the automated emails sent from the customer.rybbon.net and rybbon.net domain were coming back undeliverable. I tried manually allowing via safe sender list and that didn't work either. Is there a way to fix this for my account?