SET(M) Right to work

Hi Guys and Girls,

I keep reading people mention that they check on home office site whilst their application is being processed and it gets updated before even they get a decision email and BRP. What is the site they are talking about? If it is https://www.gov.uk/prove-right-to-work then what do we use to check it?
When I use the option @I have a UK Visas and Immigration account@ it does not recognize the old biometric card.
When I use the option @I have a biometric residence card or permit@ it says Your biometric residence card or permit is not valid
Your biometric residence card or permit has either:

expired
been reported lost or stolen

Just wanted to know if I am at the right place and using the correct option.
Many thanks,
Ray

There is no way to check the status of an application. Please wait to hear back.