links to wordpress site disappearing and re-appearing

Hi,
I have written a plugin for wordpress that uploads all images that are uploaded to the website automatically in the dropbox. This means the images are not stored in the website and therefor it requires less resources.
I created a share-able link with the function: createShareableLink($path) in the api . How ever after about 12 hours all the links were broken and 20 min later they were all back again without any changes having been made. This happened twice. This means that all the images on my site disappear at random and just reappear again a while later.
Do you know why this is happening? Can you tell me what to do?
I would greatly appreciate your input.

Thanks,
Bob Moore

Edit: private email address and duplicate topic removed by forum moderator