AMQ5540 and AMQ5541 seen between WebSphere Application Server and WebSphere MQ

So I'm seeing: -

AMQ5540: Application 'WebSphere MQ Client for Java' did not supply a user ID and password

AMQ5541: The failed authentication check was caused by the queue manager
CONNAUTH CHCKCLNT(REQDADM) configuration.

from WebSphere MQ 8.0 when I attempt to connect from WebSphere Application Server (WAS) to a Queue Manager.

The solution ?

Read this IBM Technote: -

AMQ5540 and AMQ5541, application did not supply a user ID and password, 2035 MQRC_NOT_AUTHORIZED

...

In MQ 8.0, a new function is introduced that requires MQ administrators using remote access to supply the userid and password. When the userid and password are not supplied or the password is incorrect, then the following error is displayed.

...

I chose to take the circumvention of setting the Queue Manager back to the pre-V8 days, with passing checking being optional: -

ALTER AUTHINFO(SYSTEM.DEFAULT.AUTHINFO.IDPWOS) AUTHTYPE(IDPWOS) CHCKCLNT(OPTIONAL)

Obviously, this goes AGAINST good practices around security, but, in this particular case, it's MY environment.

YOUR mileage WILL vary.