Trying to connect through a proxy but cannot connect to proxy server

We have two proxy servers available at our facility. An internal at 172.x.x.x that connects on port 8080 and requires our domain username and password. A second one at 10.x.x.x that connects at port 8080 and according to my IT group should not need a log in. I have tried both servers with and without a login and also on ports 80 and 8080. In all instances I get this message during the connection test, " HTTPS dialog failed. (Could not connect to proxy server)" Can you provide any more information on what this is telling me besides the obvious?

Hi Chester,

Can you take a look at the doc below and see if these ports are whitelisted on your network?

Thanks
-Tim

Can you do something like this with a VPN or it has to be a proxy?

No, you cannot connect to our VPN through another VPN.

Usually the problem could be from the proxy provider you have, or if the proxies are free they could be damaged. I am working in a SEO company for some time, and we are working only with proxies, they are more practical for us. One day all our proxies servers went down, and basically a SEO company can’t work without a proxy, each of us started looking for some free proxies to work at least until we will find the permanent decision. These proxies were good for only 1 hour, after they went down as well. At least in this hour I wasn’t doing my job, but was searching for a proxy provider, and I found https://iproyal.com/residential-proxies/ who gave us some proxies with a very good price per GB, it was 2 years ago, and we are still working with them, I recommend you their services.