Our company uses google apps for businesses which allows us to use a custom domain for email addresses.

Few of us are using outlook.com and just added our company's gmail account to our outlook.com account (as send only address).

Lately, once a week or so, whenever we compose new emails in outlook.com and put ANY of the company's email addresses in, the email address has a red rectangle around it and hovering over it says "The address may not be valid".

It doesn't matter what we try - restart everything, refresh, restart our modems/routers, move the computers between the home/office etc. - outlook.com still complains about the addresses.

If we ignore the warning and send the emails, it just bounces back (even though it works just fine when sending the emails through gmail.com).

Also note that all the emails bounce even when we send them on our windows phone devices (outlook again).

When that happens we need to switch back to gmail (which sucks) until the problem is gone.

It usually takes about 24 hours until the situation gets back to normal.

The addresses are definitely valid, as we keep using them outside outlook.com when the problem occurs.

I even tried sending an email from my company's email to the same email and it bounces. It's like outlook can't send to that domain at that point no matter who the sender is.

Any idea what's going on?

Thanks,

Yudi