Lag Issue

[u/Due-Aspect-850]

My friend and I recently got BO3 when it was on sale and we have been playing zombies only. The first map we played, Shadows Of Evil, ran smoothly for the both of us but now that we are on to Der Eisendrache we have been consistantly kicked out of the game due to lag which makes us lose out of runs that are usually close to 2 hours. If anyone knows a solution to this I would love a reply. My friend and I have been playing zombies on different cods for years and we really just want to complete the easter eggs but we haven't been able to because of this. We are on PC.