I'm using MS Outlook for Mac 2011 - on IMAC 

For years I have been sending emails to a group composed of 26 members.  This a.m. the email sat in my outbox for ages before I noticed it had not been sent.  I check the other posting for possible problems including checking each email address for a malady....none found.  One comment suggesting sorting the list but I don't find a way to do that, so any suggestions will be appreciated. 

All assistance will be appreciated!