Well, I tried to upload the same geometry again (not re-uploading, but new model), and that went fine.
But the initial uopload gave an automated response of SW telling:
"Unfortunately, the model you recently uploaded T3095b20160320r did not pass our initial printability checks, so it's not yet ready for 3D printing. Please visit your 3D model page to ... "
It looks like the uploading process took forever and that the 'checker' doesn't complete the entire upload procedure or something.
A similar -but not fatal- situation can be noticed with the wall thickness checker. If you're uploading a model and go to the viwer, you will see that initially the model is shown as completely 'red' too thin. Only after a while (your website is slow) the geometry gets completeted and the model turns green.
Other actions like adding text to the product didn't go smoothly. The SW editor showed signs of dementia. Text was gone after 'saving'.
Probably the website was busy. But it should not happen. I think it needs to be checked.
Regards,
Maurice