Coming back to the SSL error, the most hassle-free way of fixing this problem (ERR_SSL_PROTOCOL_ERROR on chrome, PR_END_OF_FILE_ERROR on firefox, other browsers might differ) on our side (as players) is to add the IPv4 address of feudalife into your hosts file.
DO NOT BLINDLY TRUST ANY PROPOSED CHANGES TO YOUR HOSTS FILE, YOU MIGHT GET SCREWED OVER. IF YOU ARE UNSURE ABOUT ANYTHING, BETTER WAIT FOR AN OFFICIAL SOLUTION. To be 100% on the safe side, look up the correct IPv4 of feudalife.indiegala.com yourself either by using "nslookup feudalife.indiegala.com" in your command prompt, or use any of the available dns lookup services. I advise everyone who tries this fix to make a copy of their current hosts file, so you can revert to it's original state as soon as the problem gets fixed by IndieGala.
To add the address to your hosts file, you need to start the text editor as administrator, and open the file "hosts" located in C:\Windows\System32\drivers\etc (For other windows versions, other operating systems or if you just want to have a guide with pictures, check
this guide)
After opening the file, add the following to the bottom of the file: 45.79.248.227 feudalife.indiegala.com
Save the file, and the ERR_SSL_PROTOCOL_ERROR should no longer appear, and there is no need to play with any network adapter settings.
This should work for now, if the game changes it's IP at some point you will have to either completely delete the line from your hosts file, or change it to the new address. This will not fix any issues regarding freezing, not correctly counted wins, duplicate keys, Please Wait signs, fetching user data issues or anything along those lines, this
only fixes the ERR_SSL_PROTOCOL_ERROR (chrome) / PR_END_OF_FILE_ERROR (firefox), and again, I advise to revert your hosts file to it's original state as soon as the problem gets fixed by IndieGala.
EDIT: To explain what this fix does: Usually, a computer can't understand the fancy words of an URL, so it asks a DNS server for the IP. Depending on your PC settings and your ISP, this answer might be provided in IPv6 format (looks something like this: [2001:4860:4860::8888] <- google DNS address, there might be letters in there aswell). For other settings / ISPs this answer might be given in IPv4 format (127.0.0.1, the classic way). Now, since Feudalife's IPv6 configuration seems to be broken at the moment, we can not connect to it on this way. The IPv4 address works without problems though, so we want to use it. To do this, we add the IPv4 address to the hosts file. Technically, the PC first checks the hosts file for fitting IPs, so it will now use the IP address written down there instead of asking the DNS. This can become problematic if Feudalife ever moves to a different IP address, so it would be best to remove the entry as soon as the problem is fixed.