End up in junk mail when sending

Hi, 

I have a problem with my Exchange 2013 server.

When I try to send out to external mail accounts I can sometime end up in junk mail.
I try to find out if it is just some certain mail that we can't send to.

I do know that we have problems with Gmail.

Could it be that our name which includes "monkey" can be mistaken for money by autofilters?.

Thanks for answers.