Hi Lily,
I was able to reproduce the issue the second time I took your experiment. I inspected my webconsole and noticed multiple 403 errors: those are called “Forbidden errors,” which means that the server will not accept the request. This means that the servers hosting your audio and image files sometimes refuse to serve some of them
Unfortunately there is not much you can do on the PCIbex Farm’s end, since it’s up to the host server to decide whether to accept the farm’s requests. It could be that admins there have added a check that blocks requests when too many are received in too short a time window. One option you could consider is to compress your audio files in a zip archive (and also your image files if you’d like, in the same or in a separate zip file) and fetch that instead of each audio file individually, using PreloadZip in addition/instead of AddHost. You’ll find more info on the procedure in the documentation. You might need to contact IT for assistance, depending on whether their webserver accepts .htaccess configuration files
NB: I recommend you share your project’s demonstration link rather than the production link, or you might end up with noise in your results file. Also, I need demonstration links, which come with a very useful debugger, for troubleshooting (which, in this case, I retrieved by looking up associations in the farm’s database)
Let me know if you have any questions
Jeremy