I don’t care about the net::ERR_SSL_PROTOCOL_ERROR
The trading post is a website. That error means you’re failing to establish a secure connection with the site.
As for the other error, post a screenshot of it so I can identify what type of error it is. I’m assuming it’s on the page itself, like when you sell items too quickly, in which case it might be an account problem or something is modifying what you’re sending.
With the SSL error, does the gem store work? What about browsing the trading post?
First, as a note, some of these are for the SSL error specifically, however they can help in both cases.
If you ignored what I said before, do it now. Additionally, in the Internet Options, under the Advanced tab, click the restore advanced settings button (you may also want to try the “Reset…” button after this, but not right now since it’ll reset everything). In the box above, scroll down to the bottom and ensure that all SSL and TLS options are checked. Under the Connections tab, click the LAN settings button and uncheck all options, then click OK and again out of the Internet Options. Reopen the Internet Options and go back to the LAN settings. Confirm that everything is still unchecked. Proxy software might forcibly modify your settings.
Setup Google’s DNS: https://developers.google.com/speed/public-dns/docs/using. After doing that, open the command prompt and enter the command: ipconfig /flushdns
Check your security software for a web/protocol monitoring feature or something involving SSL and disable it. BitDefender for example has caused problems in the past. Also note that simply disabling your anti-virus as a whole may not be enough. Some will continue to function regardless.
Search your start menu for cmd, right click cmd.exe and run it as an administrator. Enter the following command, then reboot: netsh winsock reset
Run Windows update and ensure that the latest service packs are installed for your OS. If there were updates to install, check again after installing them and rebooting.
Turn off your router/modem for around 30 seconds. If you can, try directly connecting to the modem just to ensure that the router isn’t causing any problems.
If you want, you could install Fiddler which is a web debugging tool that acts as a local proxy. It’ll allow you to see the requests being made as well as the responses. If you’re encountering any certificate errors, it will allow you to ignore them. You might be able to see a more specific error by looking at the response when selling an item.
Setup a VPN (use a free trial of WTFast or something) and run the game through it. This will determine if your ISP is causing the problem.
As a last resort and assuming a software related problem, reinstall Windows. Alternatively, try a different computer or temporarily install Windows on a removable storage device. Before doing this however, you may want to first try disabling as much software as you can. Press WindowsKey+R and open msconfig. Under the Services tab, check hide all Microsoft services and then click disable all. Under the Startup tab, click disable all, then OK and reboot.
