Recurrent problems with Windows Live Mail: Server error 3204 etc.

I am having recurrent problems with Windows Live Mail. Sometimes I get the 3204 error message (Unable to send or receive messages: Server error 3204. Windows Live Mail Error ID: 0X8DE2003), and sometimes WLM will not open at all.  I employ a number of strategies to get it running: checking for mail stuck in the Outbox, deleting my two accounts then adding them back, running WNL diagnostic, repairing Essentials, uninstalling Essentials then reinstalling, running CCcleaner, running System Restore. Eventually something works, although I can never predict which. Frustratingly, the fix only lasts a few days...WLM has gone down five times since I started keeping a log on November 18. Where do I go from here?