Check /opt/qradar/conf/nva.conf and see if the CONSOLE_FQDN field is actually reflecting the true host name.
If not, use the /opt/qradar/bin/qchange_netsetup utility to change the host name. Make sure you save the passwords and IPs of the removed MHs,
Because you need to re-add the MHs after the script finishes.
https://www.ibm.com/docs/en/qsip/7.4?topic=nsm-changing-network-settings-in-all-in-one-system
Detection knowledge repository – by Daniel Koifman