User f0def15fb15b was denied access.
Fully-Qualified-User-Name = mydomain\f0def15fb15b
NAS-IP-Address = 192.168.10.245
NAS-Identifier = SW-5
Called-Station-Identifier = 00-16-b9-d2-99-d9
Calling-Station-Identifier = f0-de-f1-5f-b1-5b
Client-Friendly-Name = Connection to Switch 5
Client-IP-Address = 192.168.10.245
NAS-Port-Type = Ethernet
NAS-Port = 39
Proxy-Policy-Name = Use Windows authentication for all users
Authentication-Provider = Windows
Authentication-Server = <undetermined>
Policy-Name = <undetermined>
Authentication-Type = MD5-CHAP
EAP-Type = <undetermined>
Reason-Code = 19
Reason = The user could not be authenticated using Challenge Handshake Authentication Protocol (CHAP). A reversibly encrypted password does not exist for this user account. To ensure that reversibly encrypted passwords are enabled, check either the domain password policy or the password settings on the user account.
If I subsequently reset the password, the user authenticates without an issue.