Just to share my experience.
After reservation, my sandbox lab is created successfully and I got email confirmation with VPN detail & credentials. I am able to login to VPN page and see the bookmark for the following servers:
- CUCM Publisher
- CUCM Subscriber
- Unified Presence
From there, I am not able to access anyone of the server above.
The VPN page displayed this error message.
DevNet Sandbox VPN Portal
Unable to connect to server 10.10.20.1 .
The server may not exist, or access to it may not be allowed.
Any idea why this is happening?