Create VSP (Onboarding method : Manual)
Do not add License Agreement, Licensing version and Feature group to VSP then try to create Deployment flavor without FG.

Getting null pointer exception while creating Dewployment flavor for Manual type VSP

BE Response :

{
"status":"INTERNAL_SERVER_ERROR",
"errorCode":"GENERAL_ERROR_REST_ID",
"message":"An error has occurred: null"
}

Add License Agreement, Licensing version and Feature group to VSP then try to create Deployment flavor without FG.

Getting below BE response.

BE Response :

{
"status": "EXPECTATION_FAILED",
"errorCode": "FEATURE_GROUP_NOT_EXIST_FOR_VSP",
"message": "Invalid request,Feature Group with Id null does not exist for Vsp with Id 7dbd234b21ac42cbae2c621bae39c112 and version 0.0."
}