I am having trouble with Outlook. I can receive emails from Yahoo but emails I send don't seem to be getting through, although I can email other types of email accounts
I had a problem with AOL accounts which did the same thing. It turned out I was put on a central spam list because someone had sent mails out under my name. I would guess this is what happened to you.
I had to contact AOL to ask to be removed from the list.
Yep. It's pointless them having central spam lists, as a spammer will very rarely use their own address. Surely we should have the choice of either accepting or rejecting our own mail?
Chances are that the mails you are sending are appearing in the other user's spam box too, so at least they are getting through.