proxy server settings error

I’m running Kodi 17 on an Amazon FireTV box and have encountered a strange problem when I configure Kodi to use a proxy server. I have a number of video files stored locally on my LAN which suddenly will not play. It’s just certain ones, and there does not appear to be any consistency in the format of those files, nor of the encoding protocols that were used to encode them – I have other files in fact which use the same formats and those will play fine.

The files that I have the problem with play fine when the proxy settings are disabled. They also play fine when there is no internet connection.to the FireTV box at all so long as the proxy setting is disaled. I also tried enabling the proxy setting, but disabling the internet connection to the proxy server – the files will not play. So it seems to be the proxy setting switch within Kodi which is causing the problem.

Anyone come across this before or have any ideas?