My Mac Outlook 2011 Stopped Sending Emails for all POP Accounts from Different Providers

I've had this problem before, but this time I am truly dumbfounded. My Outlook 2011 has randomly stopped sending emails, but I can still receive them. This has happened a few times and I normally change the ports/SSL and I can get it to work. But now I am at a loss. I have several email accounts that I manage. One of which is GMAIL, using IMAP, and this is the only account that currently works find receiving and sending. My POP accounts, four of them, all cannot send emails. They can only receive. One of them is with GoDaddy, and the other three are with an Asian company. I can't find any help on this. I've upgraded Office to the latest version. I've even deleted the accounts and added them back in, and I still can't send email. I'm frankly getting exhausted and sick of this type of problem happening. I honestly use this program and my MacBook Air to send clients information...only to find out hours later that a mail never sent because it's been stuck in my <hidden> Outbox in Outlook 2011. This has hurt me now badly on several occassions. Please HELP!