SVG not uploading, even after fitting qualifications

Hello, I tried uploading my SVG files (for the sleeves of a shirt since it has to be vector) and it says "We only accept “.png .jpg. .svg .ai .cdr” even though I am uploading a svg file. I fit every qualification for the design and export my files out of illustrator with the “Presentation Attributes” option as well and it still doesn’t work…

This is very annoying as you can tell. Spreadshirt needs better error messages. I know that isn’t the highest priority, but it is indeed very frustrating. Anyway, thank you for your help.

If you have fonts in the design, make sure these are converted to vectors.