Hi Karthini,
You might experience this because of the following issues.
It may be due to outages for the Text Analytics API in your Azure region.
Check whether your endpoint and region are correct.
Check whether you have funds in your account. If you are using trial version check whether it is active.
Check if your credentials or authentication tokens are valid and have the necessary permissions to access the Text Analytics API
Ensure that there are no network or firewall restrictions that prevent your application from accessing the Text Analytics API.