Summary
While attempting to share a folder in Sharepoint, user may receive the error message that says "Sorry, we are unable to reach the server right now. Please try again later." This is most likely caused by too many items in a folder being shared.
Body
While attempting to share a folder in Sharepoint, user may receive the following error message:
The error message is misleading because the most likely cause of this is that a folder that is being shared contains over 50,000 items, which is a hard limit of Sharepoint as documented in this Microsoft technote. The recommended workaround is to move some items out of the folder, or select individual files to share, or to create and share a new folder that contains less files and subfolders.