Hello Morag,
Thanks for your answer.
For me, when I read "default location", I understand "default path".
I hadn't realized that "default location" meant "default path/key".
Indeed, by renaming my keystore to "key.xx", it works much better.
The problem with this command is that if the keystore doesn't have the default name and path, dspmqcert doesn't work, even though this name and path can be read in the Queue Manager's SSLKEYR parameter.
Normally, with just the name of the Queue Manager, the command should be able to locate the keystore.