Cognizant Technology Solutions — Unable to login to one cognizant portal

I'm not able to login to one cognizant portal, it's displayed as 'sorry trouble In singing you' and in March I have received internship offer letter via college and I have accepted that submitted documents. And after a month I got mail to submit documents but to submit the documents unable to open portal . Please help me I'm facing this issue from many days

AADSTS90072: User account '[protected]@gmail.com' from identity provider 'live.com' does not exist in tenant 'Cognizant' and cannot access the application 'https://onecognizantexternal.cognizant.com'(ENT_onecognizantexternal_SAML_PROD) in that tenant. The account needs to be added as an external user in the tenant first. Sign out and sign in again with a different Azure Active Directory user account"
Request Id: f1246146-be5d-433d-806a-4ed91b7a6300
Correlation Id: 39eef758-ea39-4fc4-b692-9bf5c296acc8
Timestamp:[protected]T03:44:59Z
Message: AADSTS90072: User account @gmail.com' from identity provider 'live.com' does not exist in tenant 'Cognizant' and cannot access the application 'https://onecognizantexternal.cognizant.com'(ENT_onecognizantexternal_SAML_PROD) in that tenant. The account needs to be added as an external user in the tenant first. Sign out and sign in again with a different Azure Active Directory user account

im afraid i might lose the offer
Unable to login into onecognizantexternal.cognizant.com