Unable to Create WorkSpaces Applications Instance – Fleet Quota Exceeded

The error you're encountering indicates that you've reached the quota limit for WorkSpaces Applications fleet capacity in your AWS account. This is happening because your current quota is set to 0 for the instance type and size you're trying to use.

WorkSpaces Applications instance type and size quotas are per AWS account per AWS Region. If you have multiple fleets in the same Region using the same instance type and size, the total number of instances across all fleets must be less than or equal to your quota.

To resolve this issue, you need to request a quota increase through the Service Quotas console. Here's how:

1. Go to the AWS Management Console and navigate to the Service Quotas section.
2. Search for and select "Amazon WorkSpaces Applications" (or AppStream 2.0, depending on the specific service you're using).
3. Look for the quota related to the specific instance type and size you're trying to use (e.g., stream.standard.small, stream.standard.medium, etc.).
4. Select the relevant quota and click on "Request quota increase."
5. Fill out the required information, explaining your need for increased capacity, and submit the request.

AWS will review your request and typically respond within a few business days. Until the quota increase is approved, you won't be able to create new fleet instances.

Remember that quota increases are reviewed on a case-by-case basis, so be sure to provide a clear justification for your request to improve the chances of approval.
Sources
The Maximum fleet capacity limit was exceeded. Requested: 1, Limit: 0 | AWS re:Post
Troubleshooting Fleets - Amazon WorkSpaces Applications
Amazon WorkSpaces Applications Service Quotas - Amazon WorkSpaces Applications