Yubico - Yubikey secret key cannot be blank

[Jeffrey Ramsay]

I'm getting the following error on a new build of 5.3.3 even though all options are set in cas.properties.

Any advise?

01:24:37.084 [localhost-startStop-1] ERROR org.springframework.boot.SpringApplication - Application startup failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'scopedTarget.yubicoClient' defined in class path resource [org/apereo/cas/config/support/authentication/YubiKeyAuthenticationEventExecutionPlanConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.yubico.client.v2.YubicoClient]: Factory method 'yubicoClient' threw exception; nested exception is java.lang.IllegalArgumentException: Yubikey secret key cannot be blank

cas.properties:

cas.authn.mfa.yubikey.clientId=4xxxxx

cas.authn.mfa.yubikey.secretKey=GMFxxxxxxxxxxxxxxxxxxxxxx=

cas.authn.mfa.yubikey.rank=0

cas.authn.mfa.yubikey.apiUrls=https://api.yubico.com/wsapi/2.0/verify

cas.authn.mfa.yubikey.trustedDeviceEnabled=true

cas.authn.mfa.yubikey.name=Yubico

Thanks,

-Jeff