This is a strange problem. We are using an Exchange 2007 server to handle the emails to and from the company. There are two main problems which are probably related.
- None of our mails sent to one single customer are ever received.
When we send any type of mail to one particular customer, they never get it. We have confirmed the address and tried to send more to other mail addresses on the same domain and they still don't receive it. No error (email or otherwise) is ever issued. (Domain related? Blacklisted?)
- Sometimes (intermittently) a mail sent to our company (can be any address on our domain) is never received.
I tried this the other day from home and sent a mail to my work address. It was never received. But then a day later i sent another and it was received fine (so the mail address is fine). No error (email or otherwise) is ever issued.
Any ideas where to start looking for causes?