Wired network connection keeps disconnecting

Solution 1:

Port speed negotiation is typically done between the ethernet port at both ends, NOT at the cable level. So while your cable will bottleneck you to 100Mbps, your system detects a gig endpoint at the other end and as such your obsolete Cat5 cable is causing the disconnects because your system is trying to push gig over the unsuitable cable, causing network timeouts and huge congestion at the network stack levels.

Either upgrade your obsolete 100Mbps cable to a standard Cat5E cable (Cat5E is pretty dirt cheap nowadays since it's the oldest standard still supported and commonly encountered nowadays) or to a Cat6 cable, or manually set the speed on your ethernet adapter. Depending on how you configure your networking (GUI or command line) will determine the process you use to set negotiation speeds.

(Depending on your answer to the question I asked in comments on the core question, this answer will adapt to how to set the link negotiation speed manually based on your response)