Upgraded plan—now says tech required

I just upgraded to 900Mps and once the modem came back on line. The app told me that there was an issue slowing down the speed (it ran at just under 300Mps).  

The app now shows the modem as offline (even though it seems to be working). It also states that a tech visit is required to solve the issue.
I’m just wondering what it COULD be. 
Unless it is some kind of a hardware issue…why would I need a tech visit? 

Any thoughts? 
thanks!