Domain join fails with -2147477501

Hi

I try to join the domain in my OS provisioning task but it fails with -2147477501. I've read EVERY post here, tried to save the OU to join in a variable but no luck. Tried to pre-create the computer-object, no luck. This is the error message in JoinDomainHandler.log:

Joining Domain DOMAIN.COM and OU OU=Whatever.DC=DOMAIN,DC=COM

NetJoinDomain() unknown error: 64

Does anyone know what error 64 means? LanDesk 9.60.2.48, OS Windows 8.1 x64

Thanks

Dom