not checking my mail

Did you just get the new update?
You might need to uninstall/reinstall.... as updates sometimes fail

Otherwise... go get and try that new version update.

I have the same issue and checked to make sure I have the latest versions of both Firefox and Xnotifier.

Suggestions?

Well, first, there's.... 

 http://xnotifier.tobwithu.com/dp/node/4

Doesn't exactly help you guys, but >> I don't have a problem with yahoo or gmail (they -do- still work for others)... but I keep them pretty simple.

When I have a stopped up account... I go to the webmail page and log in manually to check for annoying prompts that get in the way.

I check for updates to browser, to X-Notifier and to SCRIPTS themselves... if you installed a custom one.

Then I uninstall/reinstall X-N, add a problem account and see if it works... then import one of my working email accounts backups. 
 - - You have backed up (exported) your accounts haven't you?
Sometimes that cleaning process makes them automagically work again.Just a "bit" gets stuck somewhere.

Other times you have to check for conflicts with other add-ons... a tedious process. Disable them all except X-notifier.
Restart browser. See if X-N starts working.

Last resort, create a new browser user profile, add only X-N ...see if it works.

Good luck.

This has been an issue for a while.
Not fixed by reinstall.
In the past an update fixed the issue and now an update has broken it again.
Guess either continually to manually check until it gets fixed again or revert to previous versions until one works.
Is there old version d/ls?

http://xnotifier.tobwithu.com/dp/node/801

How many accounts do you have... are they all 'broken' or only one? Which one?

Mine work fine... gmail, hotmail, outlook.com, mail.com, yahoo, AOL, local ISP, linkedIn, facebook, tumblr, twitter, ebay.