3CX relies heavily on downloads.3cx.com, currently hosted in France. Download speed from this server is only about 30 KB/s from multiple customers in the Western U.S. Downloading a 24MB phone firmware update takes 13+ minutes, which means it will always fail due to the 4-minute timeout. (Extending the timeout is possible but unsupported.) Downloading the 158MB 3CX installer takes 2 hours. Please research and implement a solution to ensure fast worldwide downloads from downloads.3cx.com. Maybe it would be enough to host at a global cloud provider (AWS, Azure), but more likely, the best solution is to use a Content Delivery Network (CDN) like AWS Cloudfront..