Specific emails are being rejected in SES

I have been sending to xxx.com from the past without a problem, but last week it started to act weird, I have been receiving bounced emails from xxx.com with a content:

An error occurred while trying to deliver the mail to the following recipients:

but yyy.com are receiving without a problem. Is this a phplist related problem or SES? At this point, I’m at lost. I have already checked my IP reputation but still got high scores and not even blacklisted to other sites.

@arnoldfudolig Do you want to try describing the problem a bit more clearly? Your use of xxx.com and yyy.com doesn’t really aid understanding.

Are you using the Amazon SES plugin for sending, or just the smtp interface?