Not an offer to help set that up but do compare the DNS you use when it works and when it does not. Change to the working DNS.
Be sure the router firewall is off for a test run (see router manual.)
Finally I see a "call sales" number at that site. It's for profit so they have tech support and it's a safe bet they know your issue.
I am having trouble accessing a website that I use to connect me to business leads so this is a problem. Every time I go to the page it tells me the website took too long to respond. I know it's coming from my network since I have no problems when I disconnect from the router an use my 4g hotspot. It won't load on my phone when connected to the wifi either. Weird thing is that it worked fine last night maybe 14 hours ago. The only thing I can think that would have anything to do with it is I recently downgraded my internet with Cox from a 150mbps download speed to 50mbps, but I've had less at another address and had no issues. I'm also unable to load facebook. It will lay out the page but never finish loading.
Google Chrome and Firefox
Relatively powerful computer (8gigs ram, corei7, Dell XPS 15 1st gen)
Already reset both the router and modem
Standard Motorola modem
Netgear model r6300v2 router
Website is https://leads.boomtownroi.com/login
Thank you in advance!