1.UDID restriction: UDID (Device Unique Identifier) is the unique identifier of an iOS device, and developers can add the UDID of a specific device to the configuration file when generating an IPA file. If the UDID of your device is not in the configuration file, Scarlet will not be able to verify and install IPA. The solution is to add the UDID of your device to the configuration file, or contact the developer to check whether your UDID exists in the configuration file.
2. Certificate expired: Developers need to sign the application before publishing it so that it can be installed and run on the device. The signature uses the developer's certificate, which is valid. If the signing certificate expires, Scarlet will not be able to verify and install IPA. The solution is to contact the developer to update the certificate and sign the latest IPA document.
3. Network problems: Sometimes due to network problems, Scarlet can't connect to the verification server, which makes it impossible to verify IPA files. Solutions include checking whether your network connection is normal, trying to use another network connection, or waiting for a while and then trying again.
If none of the above methods can solve the problem, it is recommended to contact Scarlet's technical support team or developers for help. They may be able to provide more specific solutions.