Network Management

Recently installed the Nighthawk and I seem to be running into issues with certain websites and apps that work fine but others either failing to open and be used both on my computer and on my phones. We can be watching our Roku with no trouble but I can't get my emails to download or send neither on my phone or my computer. I can stream youtube on my computer but I can't get google mail to function in the browser. When I run the test speeds for the nighthawk app everything looks normal yet I am running into this issue. Is this due to my router trying to control usage if so how I do I fix/change/manage that?

Help I work from home so my internet is crucial.

Chad