It happens VERY rarely that I have sync problem on my iPhone,.
Here is a list of the things I check or do when it happens:
- Check the Internet connection of your device
- Check Evernote status blog http://status.evernote.com/ and the Twitter account @evernotestatus
- Check the activity log in the Settings
- If there is an offending note shown in the log, copy/paste the content in a new one and delete the bad note and don’t forget to empty the trash
- You can also force quit the app on iOS and relaunch it (you should not lose any data even if it is not yet synced)
- Contact the official support, they are pretty fast (you can’t even do it via chat if you’re Premium)
Until the next time, happy evernoting!