Multicolor and textures not showing up in preview?

I uploaded several times models with one or multiple textures included that were generated by oculus medium or blender but for some reason the Materialise robovisionar only shows the textureless object after a long time …
Other programs I tried (like sketchfab, google poly, meshmixer, meshlab, blender) show the same object correctly with the textures applied and as expected. Is there something I’m missing in regards to any requirements for the textures as needed by materialise ? Is there any debug info that can shed light on why the textures are not applied at all ?
The obj file comes packed in a zip with the mtl and png textures included.
I’d really like to try out the multicolor+ stuff but first the textures need to show in the preview window I guess…

Thanks for any advice or shared experience on this (and sorry if there is something obvious I might be missing !)

Good Afternoon,

Unfortunately there are problems with the online view at this moment. We are working on a solution. Hopefuly this will be operational again in the near future. We can assure you that you model, has the necessary colors included to ga ahead with your order. If there are any problems with the file after placing your order, our customer support officers will check it and let you know or refund you immediately the full value of your order.

Thank you & kind regards,
Annick Vandezande
Customer Support Officer.