u can try this few things for android :never use minification on js... maybe some image compression but that is about it... apk + js minification doesn't play well.
html5 if this happens: don't use minification, disable adblock as might block some js required files to load Construct, clear cache of browser(images/and particular app data for the specified url).
for both, if u did the above and still have the issue, make sure all ur files are named corectly in the exported zip folder or the assets folder inside the project u get when u export.
if they aren't might cause a loading failure, usually this happens with sounds/music files that have both ogg+m4a format, that is why is better to use mp3 or just ogg.
don't name ur files with Capital leters in beggining example: Audio_Awesome_file.ogg. just name it audio_awesome_file.ogg since the capitalization will be removed upon the export, there might be a mistmatch in finding the file, remember in code the word "Awesome" is not the same as "awesome". capital letter matter.