players can't hear placing blocks sound my server is 1.12 and players use 1.8.9 also all minecraft sounds are bugged and players hear lighting sound instead of all sounds.
https://dump.viaversion.com/78716f7e1b52769cd7a069381fa54cf900782911649ca47db2b3185e6901ecb6

Next time please follow the template.
To fix your issue please also install ViaRewindLegacy-Support.