Hello HomerJ,
This is a new issue in all the versions and according to the KM document (KM03084753 ): https://softwaresupport.softwaregrp.com/doc/KM03084753
The document references the latest patches (in this case patch 7 for ALM 12.21 and patch 2 for ALM 12.55) as the official fixes for the issue as the publisher has officially changed and other versions beside 12.55 are being affected as well and future patches in those will resolve it.
There is a work around in the interim: It is possible to start ALM client only if the new Publisher (Micro Focus Group Limited) is added to Trusted Publishers according to the document.
Hope this helps resolve the issue and if not I would suggest that you open a support case with your support group to address this issue for your particular environment.
Dan