There were a couple of updates on Minion earlier, have you checked there? Tbh I know they were libs but not sure if they affect TTC, my brain is like Swiss cheese trying to remember which libs it was!

I am in game atm, have the client open and currently scanning a store, I've seen no errors.

If it says it is already running then the exe is still opened in background, check via the taskmanager and close it.

being blocked by anti-virus but completly disabling anti-virus the issue still occurs

The solution is to add it to the antivirus's whitelist and not disabling antivirus to make your system open for all threads

Did you try the whitelist already? Already whitelisted the "live" folder + subfolders in your antivirus?

What could be is that your internet IP is blocked somewhere, or are you using any VPN connection? Disable it or use another server so you get a new IP address.

Is this link working for you, or also blocked? https://eu.tamrieltradecentre.com/pc/Trade

Check that your computer is not accidentaly using a Proxy to connect to the internet and if it does and you did NOT enable that check your PC settings for malware.

I uninstaled TTC from Minion and reinstalled and now it works.

I guess your whitelist helped than later/now as it was already blocking files on first install/update of TTC and that raised the errors.