Hi I am trying to start the designer through the URL "

Anuj, if I understand correctly:

1. You can see the login page
2. Executing from a command prompt <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat -s
reports all engines are in Okay status
3. The only issue is you can't login with the default credentials. Correct?

Is this a new install? Because every time you install Appian you can login with the default credentials only once, because you are asked to change the password for this account. Most likely what happened was that you or somebody logged in using the default credentials, he/she was asked to change the Administrator password, he did it and now nobody remembers the password.

Anuj, if I understand correctly:

1. You can see the login page
2. Executing from a command prompt <APPIAN_HOME>/server/_scripts/diagnostic/checkengine.bat -s
reports all engines are in Okay status
3. The only issue is you can't login with the default credentials. Correct?

Is this a new install? Because every time you install Appian you can login with the default credentials only once, because you are asked to change the password for this account. Most likely what happened was that you or somebody logged in using the default credentials, he/she was asked to change the Administrator password, he did it and now nobody remembers the password.