In the CA7SRVR task, we have a MIXPW option which indicates whether mixed-case passwords are supported. Possible values are YES and NO. If this keyword is not provided, the default is YES. If MIXPW=YES, the password used when a CA7SRVR session is initiated is case-sensitive when security is checked. If MIXPW=NO, the password used when a CA7SRVR session is initiated is upper-cased before security is checked.
Another reason for this error could be that your username does not have access to the CA7SRVR.ACCESS resource within your security product.