Ec2 instances exceeds the limit of 1 available. why?

I created a fleet for auto scaling test. But always I can’t increase maximum instance count.

It was not applied with the message below.

“c5.large maximum EC2 instances exceeds the limit of 1 available.”

Service limit is 20, but allocated only 1 instance.

Hi, it’s likely because your account is new or has insufficient identity data. Please contact an AWS Support via the Aws Support Center to get your restrictions lifted.