Recently I switched internet providers, and so I was provided a new router (which is locked to the ISP so I cannot use my old router) with a new IP. After setting it up and port forwarding my server ports, everything seemed to work, and
canyouseeme.org could see my open port 21. I changed my PC's static IP to match the router's range and I re-configured my IIS FTP server with the new IP. I can access the FTP server from within my LAN, no problem. However, when I try to access it from my public IP, things begin to fail.
The browser requires authentication, as usual, but when I put in my Username and password, the browser loads for a bit, and then prompts me again to enter my credentials. I an 100% sure I am using the right credentials as I can access the server from the LAN with those same ones.
I have tried it with the AndFTP app on my phone and the same thing happens. I do not understand why this would happen when everything seems to be properly set up, especially since I can access my VNC and teamspeak servers without a problem.
I have tried disabling the firewall completely, but no luck.