Outlook email problem

I wrote about this problem before to the support team, but i think they dont know bout the solution.we are using mail.magnusts.com. The problem is: mails from magnus to magnus account are not working through outlook. but from direct magnusts webmail accounts, its working.
I think, all mails are sending from outlook to magnusts accounts, are caught as “spam/something like that” in the dreamhost/web server, so they are not reached in the web mail accounts. I think now its clear.
Any solution to troubleshoot?
*) And actually whats the problem of dreamhost team?

is your ISP blocking the outgoing mail port? most likely it is. change the outgoing mail port from 25 to 587 and try to send an email. make sure you remove all the mail that is currently in your outbox because they will continue to give you errors.