[FROG] IS-IS HMAC-MD5 Authentication Not Working

Hi all. So I've been trying to get IS-IS to talk to a Cisco IOS XE box with HMAC-MD5 authentication, with no luck. I created an MD5 hash of the clear-text password, and also tried it with the clear-text password, and neither work. Cisco says the neighbor has the wrong password. There is an example for doing this with authentication at the bottom of http://docs.frrouting.org/en/latest/isisd.html , but the actual configuration example does not say anything about authentication. Thoughts? Mark.