We apologize for the inconvenience caused, as per the description above, you are not able to convert a PDF file into PowerPoint file using Adobe PDFPack, Is that correct?
Using the Adobe PDFPack you can easily convert a PDF file into a PowerPoint file, please use the URL to convert a PDF file into PPTX https://cloud.acrobat.com/exportpdf with your Adobe ID and password, try it on a different browser like Chrome, or Firefox, or Safari.
You can also use the free desktop version of Adobe Reader to use the services of Adobe PDFPack, just sign in with your current Adobe ID and password in Adobe Reader. To download the Reader use the URL Adobe - Adobe Acrobat Reader DC Distribution
You may also refer to Supported file formats | Export PDF, Adobe PDF Pack
For more troubleshooting, you may refer to Troubleshooting Create PDF, Export PDF, Adobe Send, Fill & Sign … services(PDFPack or Document Cloud Services).
Hope this helps and let us know how it goes.