Authenticating using Webapp

trying ti authenticate from salesforce using the below URLs through webapp using the client Id and secretsand updated the callback URI in the app .

Authorize Endpoint URL||

|Token Endpoint URL||

navigating to companies house page

This page cannot be found

Check that you have entered the correct web address or try using the search.

If you still can’t find what you’re looking for email

but the status is still saying Pending. can u please guide us what we are missing ?