'Provided Authorization Grant is invalid' error while trying to login a dockerized application using

I have dockerized our Angular application which have been using WSO2 as API manager . After doing the configurations, i was able to run the application successfully and able to hit all existing api's. The only issue arises when i tried to use oath2/token api for performing login operation of our customer . Even though, the same code was used to perform authentication earlier(before dockerization) without any issues,now i am getting error as

{
  "error": "invalid_grant",
  "error_description": "Provided Authorization Grant is invalid"
}

Token generation api for login :

https://<myapplicationurl>:9443/oauth2/token

Errors am getting in docker console while trying to login using username 'devtest7@mailinator.com' :

Things to note :

• WSO2 AM version is 2.1.0 , WSO2 IS version is 5.3.0
• Arguments(headers & parameters) for the request is the same as that used earlier(except the username and password).
• I am able to create a new users and the corresponding user is listed in Carbondb users list.
• The issue exists while trying to login using existing user as well as newly created users.
• I have recently generated new ssl certificate for the application.
• Able to login using super admin only . Login using newly created email and username is not working.

I tried solutions seen on stackoverflow which doesn't fixed my issues. Can any one please help?