[Freeipa-users] "No valid Negotiate header in server response" error when trying to install

Hi all, 

I've been having an issue recently where my servers can't install
FreeIPA due to this error: 

Cannot connect to the server due to generic error: error marshalling
data for XML-RPC transport: message: need a <type 'unicode'>; got 'No
valid Negotiate header in server response' (a <type 'str'>)
Installation failed. Rolling back changes.
Unenrolling client from IPA server 

Restarting FreeIPA (ipactl stop, ipactl start) solves the solution, but
not permanently. 

I captured the FreeIPA logs during that event, which you can see here:
https://pastebin.com/WL7Cg90V 

Any ideas what's going wrong? One solution would be to have a cron
restart FreeIPA nightly, but that's not ideal. 

Thanks,
Greg