iPhone Ineligible for Sideloading? What to Do Next

My BuildStore device says Ineligible
Ineligible means Apple has temporarily restricted your device from registration for certain certificate-based installs. Check the device status in the BuildStore account you used for the plan. If you cannot see what to do next or how long your device may be affected, contact BuildStore Support. Include your device model, iOS or iPadOS version and the exact status or error. A new BuildStore purchase does not change an Apple device restriction. Apple’s device registration reference
How long does it last?
Apple documents an ineligible period of up to 30 days under certain circumstances. The BuildStore Terms refer to a 14–30 day cooldown following a certificate revoke. Those sources do not establish a first-time versus repeat schedule or an end date for your device. Use the device status or a support update for your case. Apple’s device registration reference · BuildStore Terms, sections 5 and 7

What your plan covers
Under the published Terms, Premium includes recovery on a replacement certificate and subscription-time coverage for the Apple cooldown after a revoke. Light and Starter do not include a replacement certificate or downtime compensation. BuildStore Terms, sections 5 and 7
If your device says Processing, see what Processing means. If apps were working and then stopped opening, follow the certificate recovery guide.