To fix the cpp:173 error in Impactor do the following:

Sign in with the app-specific password you generated. If you forgot the app-specific password or need to create a new one, go here.

This happens when Apple ID is set to 2 step confirmation or 2 factor authentication is set. In this case, it is necessary to create an application specific password by following procedure and log in with the password.

Go here Enter your Apple ID and password to login Click " Generate Password ... " under "APP - SPECIFIC PASSWORDS" in "Security" item Enter an arbitrary title in the box labeled "Enter a password label" (eg Cydia - Impactor) Copy the new password displayed under "Your app-specific password is:" Launch Cydia Impactor again, drop any IPA file, then enter the Apple ID and the new password above to install IPA.

Last updated on 9th Jan 2019