Same gear, new house & ISP - ISSUE: Refreshing websites constantly

Hello everyone, I am brand new to the community!

I purchased a AC1750 Nighthawk Smart WiFi Router back in October, along with a Netgear CM400AZNA modem. I was with Xfinity up until the beginning of December, and I was having no issues.

I just recently moved into a new home, and Xfinity was not available - I had to settle for Charter Spectrum. With Charter I am experiencing the following issues/inconsistencies with my service. Charter was no help, told me to run a Speedtest -_- and then go to my Router manufacturer for help, THANKS!

- Modem has an amber upstream light, previously it was green on Xfinity

- Websites that I attempt to load on all devices (phone, PC, tablet) require me to press the "Stop - X" button, and "Refresh" once or twice, in order to load the website.

What could cause this, and what information should I provide in order to help resolve this?