If you can’t upload images to your profile or thumbnail widget you’ll likely experience an caching issue with WordPress. Read below a quick solution for this error.
First please make sure your myb WordPress Theme is up to date and if needed update the parent theme of your myb Theme. Next you need to get rid of the caching both in WP and your browser. After deleting the cache please logout and close your browser and try anew.
If this does not work immediately with the first try please try use for a short temporary time a different browser so we can fully flush the cache. Normally this should do the magic and your widgets should work again like a charm.