On Tuesday April 26 2022 we released important updates of our solutions for data acquisition from machines with Siemens Sinumerik controllers that run OPC Classic which is based on Microsoft's COM/DCOM technology.
FIG.1: Siemens Sinumerik 840D
Already in June 2021 Microsoft introduced DCOM Hardening with new authentication requirements for programs that rely on DCOM for communication. This causes software that does not meet the requirements to stop working. These changes are automatically applied by Windows Update. Details and temporary workarounds can be found in this MS Knowledge Base article.