Some added info as I've been fighting the Host Connection Timeout issue upon login for several days. Basically you log in, can move for about 30s, then it gets stuck for a few seconds then goes to Host Connection Timeout. Repeat, and eventually after 20-30 attempts, I can stay in, usually after I move away from the base.
After many experiments, I discovered it only happens when trying to login or bed-into two bases near the shore, and they both had a lighthouse in render range. One of the lighthouses was mine, so I demolished it. And voila, gets rid of most of the issue. Sometimes have 1 Host Connection Timeout still, but no longer takes 20 attempts to log in.
My guess is it is due to large amount of structures rendering in, especially multiple galleons. And critically exacerbated by a lighthouse.