The time in seconds to wait before giving up on an agent connection. Default value is 120 seconds. If you are using a custom image, this should be set to a higher value since the image is not cached. If a non-cached image, please use at least 600 (10 minutes). This timeout is how long to wait for the connection of the agent to Jenkins controller. (this includes the queued and provisioning time from CodeBuild)

Anything less than 60 seconds is unrealistic. Even for pre-cached images on CodeBuild environment it can take up to 60 seconds. Minimum value supported is 60 seconds.