I wish I had seen this a few minutes ago. I recognize the bottom line that says ‘pluggable.php on line 876’. Same exact error I had, same line. Every time I made a change to ANY plugin, I would get that error. I fixed it by removing a plugin, although I can’t remember the exact name of it. I think it was called ‘Custom Ads Sidebar’ or something along those lines. Delete that plugin, and all will go back to normal.
If you don’t have that particular plugin, then start re-naming plugins one at a time until you isolate it. Hope that helps you.
