Explanation:

Comprehensive Detailed Explanation
You're creating a resource that will handle sentiment analysis (Language) and OCR (Vision) with a single key and endpoint. That is a Cognitive Services multi-service (Azure AI services) account.
When creating any Azure resource via ARM (HTTP/REST), the URL must be scoped to a subscription, not a tenant, and use the correct resource provider.
Scope segment: Use
https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{rg}/providers/...
Therefore, choose subscriptions/8d3591aa-96b8-4737-ad09-00f9b1ed35ad (not the tenant scope).
Resource provider: Multi-service cognitive account is under Microsoft.CognitiveServices.
The full path to create would be like:
/providers/Microsoft.CognitiveServices/accounts/{accountName}?api-version=2021-10-01 This creates a single Cognitive Services (Azure AI services) resource that provides one endpoint and one key across multiple services (e.g., Language for sentiment analysis and Vision for OCR).
Microsoft Azure AI Solution References
Azure Resource Manager: Create Cognitive Services account (Microsoft.CognitiveServices/accounts) using REST and API version 2021-10-01.
Azure AI services (Cognitive Services) multi-service resource overview-single key/endpoint across services.