that 75 nodes with 49047 height are just a few oddballs peers that are scarcely reachable, look at the map this is Bitnodes who publish it regularly  IP that responds to their probe, even they published old, testnet, forked or misconfigured clients, so you will counter a small group at the wrong height.

There are plenty of cause why nodes could reject your core, most often the difficulty lies on your incompatible protocols also your pruned or partial nodes that do not render the full data. Sometimes your strict tor setup or peer bans is causes of such situation. also you have to look into your firewall and port issues. Whatever it is very wonted to get rejected even when you connect directly.

The best you could do just debug it, except it there is no solution.., you could check your in inbound reachability like port or UPnP or firewall, this is typically where you could find the excuse. Also dont forget to check your node logs & version.