You are trying to transfer an iOS app from one developer account to another, and you encounter “New app transfers are not allowed in the App Store Small Business Program. If you initiate or accept an app transfer, you will not be able to enroll in the program or will no longer be eligible to participate in the program.” warning.
This notice is received when the transferring and/or receiving developer account is using the App Store Small Business Program. Due to Apple's own restriction, if an app transfer to/from an account under that program is initiated after December 2020, this account will no longer be eligible for the program. If you need more information, please check with Apple directly as BiznessApps can't interfere with their guidelines.