Auth0 Lock Check session returns Login required error

I am using checkSession in auth0 lock API and am passing my client id and domain.It was working perfectly in earlier stages and now its returning “login_required” error. Any idea why its happening? Following is my piece of code

 var lock = new Auth0Lock( be_params.clientId, be_params.domain ); 
    lock.checkSession({ redirectUri: be_params.siteUrl }, function ( error, authResult ) {

Hey there!

Haven’t you changed something else in the meantime?

Nop, i didnt changed anything in backend

I’m asking cause you said in your initial message that it was working perfectly in earlier stages so it shouldn’t stop working out of nowhere