NPS with azure is crashing

In azure, I have set up a VPN gateway which works perfectly for site-to-site. I had a point-to-site set up using certificate authentication, but needed to change to user authentication to allow for better accounting and access control. I set up NPS on a VM in azure, using the Azure MFA installer and some instructions I found online. The set up works fine... for a couple of days, then I start gettting the following error in the logs:

Faulting application name: DllHost.exe, version: 10.0.14393.0, time stamp: 0x57899b69
Faulting module name: MfaNpsAuthzExt.dll, version: 1.0.1.20, time stamp: 0x5aadc5f6
Exception code: 0xc0000005
Fault offset: 0x000000000002c86e
Faulting process id: 0x868
Faulting application start time: 0x01d49d7468a2deae
Faulting application path: C:\Windows\system32\DllHost.exe
Faulting module path: C:\Program Files\Microsoft\AzureMfa\Extensions\MfaNpsAuthzExt.dll
Report Id: 8112c1fe-c25c-4038-86f1-b30bc0487f9c
Faulting package full name: 
Faulting package-relative application ID: 

As you can see, the one of the DLLs in the MFA package is crashing, causing an access violation. I have tried repairing the install and then removing and reinstalling, but neither help. If I reboot, it will work for a few days, then crash again.