
Explanation

Step 1: Generate new keys in the Cognitive Service resources

Step 2: Retrieve a token from the Cognitive Services endpoint
Step 3: Update the custom application to use the new authorization
Each request to an Azure Cognitive Service must include an authentication header. This header passes along a subscription key or access token, which is used to validate your subscription for a service or group of services.
References:
https://docs.microsoft.com/en-us/azure/cognitive-services/authentication