Facebook works, messenger.com is a blank page
I can log in to facebook.com. I cannot get Facebook Messenger (messenger.com) to open in a new tab. White page.
Opaite Mbohovái (1)
Make sure you are not blocking content.
Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.
A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?
One issue that seems more common lately is Firefox's Tracking Protection feature. When it is blocking content in a page, a shield icon will appear at the left end of the address bar next to the padlock icon. This article has more info on managing this feature: Tracking Protection {web link}