In that context, “provider” means a live TV service you pay for that includes MASN.  Traditional cable, satellite, or a live TV streaming service.  Not your internet service provider.

Yeah the internet provider should be authorized  so the customer can use it like,cox,xfinity,Verizon and others are!

No, they are cable TV providers (in addition to internet).  The customer must pay for a TV package to qualify to stream MASN.

I have a package sling but masn said it's up to the providers 

I have Cox cable with no TV package and if I signed into that app it will give me the same error  since I don't have TV service through them.

Sling does not carry MASN.  Try Fubo or DirectTV stream.

So you know Verizon fios is on masn list of providers to log in with a code

I know this but$90

Fios is also a cable TV provider.  If someone only had Fios internet, that’s not enough.  As @gramps28 said for Cox. 

And yes, cable TV is expensive.  Sports is the most expensive part.