End of script output before headers – multiple apache error_log errors

I develop any changes solely on my local computer and cannot find a single line referencing this problem in my local logs.

You should always try to simulate your production environment on a dev environment. For server specs this might not bee easy, but at least the running software should nearly be the same. This includes Apache version + loaded modules, PHP, MySQL, etc as well as their configurations.

Then check if error occurs locally. If so, turn off plugins one by one and check when error disappears to get a hint on whats going wrong.

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