Active Sync Not Working

Active Sync Not Working

I've had problems with Active Sync in the past and always get frustrated and give up.  It will work for a while then not work.  I go through the motions with support and it works again.  Now it's not working again.  If only you guys could get Active Sync to work consistently like every other mail provider out there your product would be top notch.  

Right now trying to sync with Windows Phone 8 and keep getting errors after setup.  After I setup it tells me "attention required" and just tells me that the credentials are incorrect.  My settings are correct on my phone, push is turned on in the admin panel.  Is there a problem on the back end that can fix this?  Thanks.