Did the 8.3 replace official repo 8.2 or does it use different naming for php binaries? The config files might be separate too.
Try using phpinfo() to check your working config. You can just place a file with the function in the root of your webserver and it should work.
It seems like the memory allowance is too low for drupal to load.
Very often they are SIP voip solutions that barely have anything to do with landlines, other than the number pattern and area prefix.