Can't Get Past Login on a Specific Website Unless Wi-Fi is Off

I subscribe to a site called KWFinder.com for keyword research. I can visit the website on my computer. But, when I login with my username and password, the website just hangs. I can disable Wi-Fi on my phone and I can get in using my phone just fine. But, there's just too much info in the site to use with a phone. So, I'm trying to get my computer to connect. Someone at KWFinder support suggested I contact my ISP to get the website white listed. Is there a place inside my account where I can do that? Or does something else need to happen?