Deselect (uncheck) the following authentication methods:
PAP, CHAP, MSCHAP.
Only
MSCHAPv2 and
EAP should be selected.
Select "
Use Point-to-Point encryption (MPPE)". Click "OK" then click "Apply".
If you are prompted to protect the keyring, enter a password of your choosing twice, then
click "OK". Click "Close" to close the Network Connections dialog.