I ahve started getting this error report from one of our customers. I can send mail to them with no problem, but when they try to reply They get the message: A message that you sent has not yet been delivered to one or more of its recipients after 25 hoursWould this be an error on my end or something on theirs?

Hi,Whether they could send the new email to you but not reply the previous email?Currently, whether this issue only was encountered on oneof the customers? If it is, it seems that this issue was the customer side.ThanksAllen