Instance launch failed

It appears you've encountered a common issue related to vCPU limits for specific instance types in AWS EC2. The error you're seeing is due to your account having a default vCPU limit of 0 for G-type instances, which includes the g4dn.4xlarge you're trying to launch.

The quota you requested an increase for, "All G and VT spot instance request," is not the correct one for your situation. You need to request an increase for the On-Demand G instances, not Spot instances.

To resolve this issue, you should:

1. Go to the AWS Service Quotas console.
2. Navigate to the Amazon EC2 section.
3. Look for a quota named something like "Running On-Demand G and VT instances" or similar.
4. Request an increase for this specific quota, explaining your use case (research project) in the request.

It's important to note that AWS puts these quotas in place to protect users from unexpected costs and to ensure gradual resource usage increases. As a new or low-usage account, you might face more scrutiny when requesting increases for powerful instance types like G4dn.

If your request is denied again, you might want to consider:

1. Providing more detailed information about your research project and why you specifically need a G4dn instance.
2. Starting with a smaller instance type or a different GPU-enabled instance if possible, to build up usage history.
3. Contacting AWS Support for more personalized assistance with your quota increase request.

Remember, AWS takes these precautions to help protect you from unexpected charges, so be patient with the process and provide as much information as possible about your use case when requesting increases.
Sources
Unable to create an Windows-server 2022 instance with instance type G4dn.xlarge in free tier | AWS re:Post
Unable to create more than one EC 2 instance | AWS re:Post