This was an issue that we had after upgrading from 10.7.1 to 10.9.1 for Server, and 10.8.2 desktop. Had a call into tech support as well.
We did have 2 or 3 SQL drivers installed - we've done this MANY times in the past on previous servers and desktops. Uninstalled all but 17 and low and behold it all worked as it should - Server and Desktop. Now will mention that the 18 driver didn't work. So we uninstalled it and reinstalled just the 17 driver and all played very well together.
We had the tech support for Server on the horn for at least three days, asking questions of other tech nearby, no one asked about this or even mentioned it. We kept getting certificate errors with the registration of the databases for Server. New certs, everything, security team helping, nothing would work.
We were confused as all get out about why we were getting certificate errors on desktop as well as server - that had never happened in the past. So I did a quick search and found this thread, tried it and have to say thanks to HendrikBritz1 for posting what you had found on another thread. Of course, will have to say that we didn't expect it to fix both issues at the same time, but are extremely happy it did.
Lorinda