In my setup, I use Apache 2.4.33 as TLS termination and reverse proxy for another http service. The service responds to all requests with HTTP 200 (verified using tcpdump) but with "Transfer-Encoding: chunked" (not sure if this is relevant). If I enable the option "AddOutputFilterByType DEFLATE application/json" in apache, the forwarded response gets compressed but sometimes (not for every requests) changes to HTTP 206 (partial content). This does not happen if the option is not set. The apache log does not show any errors. The issue has already been posted to the mailing list but without any response: https://www.spinics.net/lists/apache-users/msg117225.html This is the reverse proxy configuration: <Location "/epg/"> AddOutputFilterByType DEFLATE application/json ProxyPass http://localhost:5000/ ProxyPassReverse http://localhost:5000/ </Location>