This is typical of the incompatibility of flash plugins added to Firefox interfering with your YouTube videos. It usually makes your YouTube to give error message on the screen while trying to play any video from the Firefox browser. The message is, ''An error occurred. Please try again later''.
Image showing YouTube error in Firefox
This kind of issue is not peculiar to Firefox alone also to Google Chrome browser. It is one of the things which keep you thinking the server is responsible for the problem when it is not. The problem is oftentimes associated with Real-player plugins which need to be disabled at the Firefox settings.
However, if you are experiencing this error in your Firefox Version 22 and earlier versions this information will help you to solve it in time.
Image showing Red arrow pointing to Firefox tab
STEP 1: Click on the little arrow pointing downward by Firefox tab at the top extreme right-hand corner of your screen.
Image showing red arrow pointing to Add-ons at the Firefox drop-down menu
STEP 2: At the drop-down menu click 'Add-ons' to continue.
Image of Add-ons Manager
STEP 3: From the 'Add-ons Manager' click on 'Plugins' .
Image showing all RealPlayer plugins disabled at Firefox Add-ons Manager
STEP 4: Look for all plugins associated with Real player and click on their various 'Disable' tabs to disable them.
Image showing Extensions with disabled plugins
STEP 5: Click on 'Extensions' at the 'Add-ons Manager' . Look for 'RealPlayer Browser Record Plugin and disable' it.
Image showing red arrow point to X to close Firefox browser
STEP 6: Restart your Firefox browser by clicking X to close it . Reopen it and visit YouTube to play your videos.