This post was written after an internal discussion with all involved developers.
The Navdata Center app and the Charts Desktop app share technical platform being Electron apps while FMS Data Manager and Simlink are c++/Qt. We have thousands of users running either app, without this issue (no other forum reports) so it is not a general issue with our apps or APIs.
During the internal discussion we concluded that the most likely cause of the error message you posted initially would be a networking/connectivity on your machine affecting the Electron stack specifically, possibly some latency issue that causes this error specifically in Electron on your machine. We cannot reproduce it on our end, but it was the best idea we had. This reply by Skysail was written 3 days ago. Now you replied 13 hours ago questioning the technical expertise in even asking this question, and then immediately with follow up posts that are very heated questioning our team members and expertise.
It is unfortunate that we were not able to resolve your issue immediately but for issues that only affect one individual and which we are not immediately able to reproduce it can take both days and weeks. There is no point continuing this as you clearly have made up your mind about our troubleshooting, and this is a forum of respect. We have refunded your subscription in full and will now lock this thread.
Regards,
Stephen