50Webs Account Not Receiving Emails

I have a 50Webs hosting account and have several emails set up for my organization. One of them is receiving emails, but the rest are not. I have tested sending emails from other accounts. I usually get some kind of error message, such as "podcast address wasn't found at your agingoutinstitute.org" or the email just disappears and never shows up at its 50Webs destination. It seems like all the "extra" emails are being rejected by 50Webs.

I need assistance identifying and fixing the problem so that all the "extra" emails receive emails and forward them to the primary email account.