Replacing amtlib.dll is the most common crack. It breaks offline verification because the file hash no longer matches Adobe’s signature. Result: crashes, missing printer features, and false virus positives.
Adobe no longer supports a purely "perpetual" offline license for Acrobat Pro DC (the "Document Cloud" series). Most current workflows require periodic online validation. However, legitimate methods exist for offline activation, primarily for Volume Licensing customers or using the legacy Acrobat 2017/2020 perpetual products.
For further troubleshooting, you can visit the Adobe Help Center to resolve common subscription and licensing issues.