{"error":{"message":"PHP Startup: Unable to load dynamic library '\/usr\/local\/lib\/php\/extensions\/no-debug-non-zts-20100525\/apc.so' - \/usr\/local\/lib\/php\/extensions\/no-debug-non-zts-20100525\/apc.so: cannot open shared object file: No such file or directory"},"errors":["PHP Startup: Unable to load dynamic library '\/usr\/local\/lib\/php\/extensions\/no-debug-non-zts-20100525\/apc.so' - \/usr\/local\/lib\/php\/extensions\/no-debug-non-zts-20100525\/apc.so: cannot open shared object file: No such file or directory"]}

I'm seeing this pop up all over - after adding a block and taking the page off edit mode (publish), that error message pops up. Any clues?

I just did a fresh install on a clean database - C5.7.3.1 Elemental theme.
Any clues? I have no idea. Help!