Showing invalid serial number

I recently purchased an iPhone 14 Pro Max, and I’m facing an issue with its serial number. The phone is PTA approved, and the model number starts with “M”, which indicates it’s a brand-new retail unit. The IMEI matches the box, and there are no issues with activation. However, when I check the serial number on Apple’s Coverage Check, it says “Invalid Serial Number.”

I’ve tried the following steps but the issue persists:

• Verified the serial number in Settings → General → About and re-entered it carefully.

• Signed out and signed back into my Apple ID.

• Restarted the device multiple times.

• Checked my Apple ID account at appleid.apple.com, but the iPhone does not appear there.

Since the device is genuine and PTA approved, I’m unsure why the serial number is not recognized in Apple’s system. Has anyone else faced this issue?