AMQ9642E: No SSL or TLS certificate for channel …

The channel ‘QMAQCLIENTTLS’ did not supply a certificate to use during SSL or TLS handshaking, but a certificate is required by the remote queue manager.

The channel did not start.
Ensure that the key repository of the local queue manager or MQ client contains a certificate which is associated with the queue manager or client. If you have configured a certificate label, check that the certificate exists.

Colin’s comment

Check the certificate label being used, and the keystore.  Check  the certificate exists.  For example

runmqakm -cert -list -db zzclient.kdb -type cms -stashed -v