System error /usr/local/wkhtmltopdf-binaries-centos6/bin/wkhtmltopdf-amd64-centos6: error while loading shared libraries: libpng12.so.0: cannot open shared object file: No such file or directory

Error: An Internal Error Has Occurred.

This was working before. I do not know why i have the error now.

This is a CakePHP support forum, not a wkhtmltopdf/linux support forum.

I understand this but i am using cakephp to run this and it has been
working before this time.

And just because you use e.g. your car key to turn on your car doesn’t mean the key is broken if your car doesn’t turn on. Nothing inside CakePHP is causing this error for you. It’s the underlying system which has a problem.

If you google that error you will find thousands of similar errors which indicate, that something is wrong with your linux installation (maybe too old, maybe not properly configured etc.)

@KevinPfeifer nice example by car keys :v: