If you see an error when posting multiple photos to online services with Photos for macOS
Limit the number of photos you send in one batch to avoid errors when posting to online services with Photos for macOS.
When you upload multiple photos to Facebook, Flickr, or other online services using Photos, you might see this error: "Cannot Post to (online service). The post cannot be sent because the connection to (online service) failed."
This error can happen when you try to upload too many photos in the same batch. Try limiting each upload to 50 photos or fewer to avoid connection errors.
Information about products not manufactured by Apple, or independent websites not controlled or tested by Apple, is provided without recommendation or endorsement. Apple assumes no responsibility with regard to the selection, performance, or use of third-party websites or products. Apple makes no representations regarding third-party website accuracy or reliability. Risks are inherent in the use of the Internet. Contact the vendor for additional information. Other company and product names may be trademarks of their respective owners.