Problem syncing Game Timer over network

I am working on making an fps with online multiplayer. I have setup a death match mode but I am cant seem to figure out how to get the game timer for how long the match goes on for to sync up with all players. All solutions I have tired myself have led to the master client being to connected and play without issue but since putting in my attempt at syncing the game time if anyone else tries to join it they cant. Help in pointing me down the right path on how to solve this problem would be much appreciated. I am using the free of version of Photon Unity plugin for the networking.

I am not using photon server but i developed multiplayer card game through smartfox server.In that game i manage timer on server side.Server send timer value to all connect player.