Any suggestion what should I do to resolve this issue? It turns out only one computer failed to update to TeamViewer 15 and stuck at TeamViewer 14.2. We are simply a university and I seriously doubt that the department will be willing to pay $200 a month for the full support because it only saves the students from walking up to the computer to run their experiments or do data transfers. Offer me some alternative license option here that I can brought up to my supervisor for a purchase and of course some solutions.
That error usually indicates a network issue with the system. Run some network tests on that system to make sure everything is running correctly. You could also try downloading the latest version and installing it that way. https://www.teamviewer.com/en-us/download/
TeamViewer user since version 6 (2010). We used other remote software programs (TVNC UVNC PCAny) for many years before.