VPN connection - Please enter your authentication information Prompt
This was a frustrating issue and I thought others may benefit from a quick write-up. I did not see a solid solution in any VPN forum or with apple. Here is what worked for me.
Note - this was caused by backing up an iphone 6 where Tunnelbear was installed and working and restoring the backup to a new iphone x...it looks like most of the others who have this issue also experienced it with backup/restore operations.
Also - I use a VPN service called TunnelBear, however, this issue appears to happen across multiple App-based VPN configurator type services.
Iphone X will forcibly prompt for a VPN password when using a VPN service.
The VPN on the phone wanted to use the TunnelBear connection to form a VPN tunnel on the wifi network that was nearby.
The issue was I could not cancel out of it. I hard powered off the iphone X and when it booted, the VPN password prompt immediately returned.
It looks like this error has happened to others - https://www.google.com/search?q=vpn+connection+please+enter+your+authentication+ information
When this prompt is up, you can hit cancel, but it will immediately pop back up. Some forum users suggested hit cancel and then attempt to put it into airplane mode, this did not work as the prompt was far too quick to return to get into the settings/menu on the iphone.
SOLUTION HERE -
Based on the airplane mode trick, I suspected it was attempting to auto-connect to the VPN tunnel on the wifi at work....so we drove away from the wifi to be on cellular only (we are set to not use VPN on cellular).
This caused the password prompt to not come up, and then allowed us to reinstall the VPN profile. This then worked. Awesome!
I attempted to submit a iphone feedback report, but it looks like those may go into a black hole at infinite loop/campus. With the gaining adoption of consumer VPN's like NordVPN, PIA, TunnelBear, and a long list of others, hopefully Apple addresses this soon!