@Dor Mizrahi Thanks for reaching out. Can you please confirm if your function app is trigger for other files such as JPEG, PNG and GIF but your Computer Vision services fails to process images and return information base?
For Community:
In case someone observes the same behavior then please verify whether your function app storage trigger is you have specified any path with the file types as in the configuration which would only trigger your function for the specific file. In case if you have already verified that you have not configured any file types path and your azure function is getting triggered correctly then please verify your application insights logs of your function app or review the Diagnose and solve problems blade on your function app if there were any error/exception in your function app that would cause the issue.