Here is a "Mathcad Prime Knowledge Base Articles" (see attachment for detailed answers) which are available on the PTC's support site. Link is: https://support.ptc.com/appserver/cs/view/kdb.jsp?Product=Mathcad+Prime&Release=2.0&DocType=kdb_article

Installation  

1. *Frequently Asked Questions - Installation
2. *Frequently Asked Questions - Licensing
3. Activation Troubleshooting - Error “You have reached the maximum number of license files available for your license type” while retrieving Mathcad Prime license via Internet.
4. Activation Troubleshooting - Error: "401: Unauthorized User".
5. Activation Troubleshooting - Error: "407: proxy authentication required”.
6. Activation Troubleshooting - Error: "503 Error: Server Unavailable”.
7. Installation - Error "You are running Windows XP, but do not have Service Pack 2 (SP2) or higher installed. This is a minimum system requirement for Mathcad Prime 2.0. Please upgrade your system" when installing Mathcad Prime 2.0.
8. Installation - Warning "Mathcad 15 M010 or later was not found on your system. It is required to convert older Mathcad documents to Mathcad Prime 2.0…” appears while installing Mathcad Prime 2.0.

Miscellaneous  

9. Can I open Mathcad 14.0 or Mathcad 15.0 worksheets in Mathcad Prime 2.0?
10. Error “Conversion Failed. Conversion cannot be started because a previous version of Mathcad is running…” appears when trying to convert legacy Mathcad worksheet to Mathcad Prime.
11. How to convert worksheets created in earlier versions of Mathcad to Mathcad Prime 2.0.
12. Launching Mathcad Prime 2.0 F000 64bit version reports an error "Mathcad Prime has stopped working" or "Mathcad Prime auxiliary support has stopped working" or Mathcad Prime does not launch after the splash screen on specific Windows 64bit machines.
13. Launching Mathcad Prime reports a warning message “You do not have a valid license” and selecting “License status”, error "Invalid host…” displayed on Mathcad options window
14. Launching Mathcad Prime reports a warning message “You do not have a valid license” and selecting “License status”, error "Terminal server remote client not allowed…” displayed on Mathcad options window.