I added custom fields to User accounts. One of the custom fields is an image field, specifically the single_image field. I added a Meta Box form shortcode to a page on my site so members can update the information in the custom fields attached to their User profile. This has been working fine for a long time.
Now, users with the Subscriber user role cannot upload an image using the MB User Profile form shortcode. They can update text fields, but they can't upload an image to the image custom field. They get the following error when trying to upload an image, "An error occurred in the upload. Please try again later." Admin accounts can upload images just fine, though.
There are no error messages in the logs when trying to upload an image.
Is this a bug? Is there anything I can do to find the issue and get it fixed?