Hmm well, that line-trace failing is odd. Does that error mention anything specific, an actor & component(s) that fail? The character you’re using likely has a camera attached to a boom (spelling? - moves the camera closer when it bumps into a wall, etc.) and it may be the boom isn’t handled well on the client when a server-triggered ragdoll occurs. This may not be a bug, but an implementation problem on your side. Ragdoll is tricky business, as is server stuff, and you’re attempting to do double tricky business. 
Perhaps settings in the player’s camera boom component may help, or somehow disable camera boom from impacting the camera on ragdoll.