I’ve tried sharing an Anki deck several times and have gotten this message every time:
An error occurred while sharing. Please ensure you can export the deck locally using the latest Anki version, then try sharing again. If issues continue, please post on the forums.
I’m using Anki 2.1.65 and have successfully exported the deck with no issues, but when I tried to share the deck afterwards I got the same message.
The misleading message should be fixed now. It was happening because your export is larger than 250MB - I’m afraid you’ll need to divide the deck up into two or more parts to shrink it down under the limit. You can export on a local device to see the size of the export.