Mail not delivering to my non-@mac address

Hello. Not sure where to post this since I'm having the problem on my MacBook Pro since upgrading it to Lion, and on my new iPad Mini.

I have two email addresses. One is my age-old .mac, then .me, then.icloud address.

The other is my local ISP address @catskill.net

I have a third machine, my Mac Pro running Snow Leopard. On it, I get mail from both addresses.

But when I go to eiother of the other two; iPadMini or MacBookPro-Lion, the messages that came in addressed to my local, @catskill address are not there.

I hacve compared all account settings and all seem identical.

I looked at mailbox settings, advanced settings, Rules, etc., but nothing appears particularly different among the three machines.

I tried sending test messages from my .Mac server setting to my .catskill address, and I do get them.

But it seems anything coming in from outside my own personal network do not.

I'm stumped. Any help?

Thanks