Sometimes VPN will say that your username or password is incorrect despite entering the correct password or even if you have ticked the option to remember credentials. To resolve this issue you will need to first make sure that the VPN is up to date, then clear credentials and entering them again.
To learn how to check for and install VPN updates click HERE.
To re-enter VPN credentials right click on the red circle and select SETTINGS or PROPERTIES from the sub-menu
You will see the following box open up. From there select ADVANCED from the top menu, and under Credentials click CLEAR ALL SAVED CREDENTIALS.
Now you can re-enter your credentials with full email address as so:
Make sure you are entering your password correctly as it will lock if you enter the wrong credentials too many times. A good suggestion is to copy and paste your password to a sticky note and copy from there when needed.
***FYI Sometimes it might be difficult to catch the difference between a Upper Case "i" and a lower case "L" (e.g. l ... I) and this might cause confusion. ***