Common mistake in Integration is the use of 99Acres portal credentials. login id and password while configuring the connector.
Clients have to check with the 99Acres team to get the User Name and Password specific for API integration.
Usually the format would be a simple User name with no @domain.com
Here is a reference ticket:
When one uses the Email id and password in the configuration panel - the integration does not work and an error gets shown on the backend logs.
Authentication error due to invalid credentials.
This information is based on the inputs shared by Argit from the dev-team.