When I tried to configure Jetpack for my new users to allow them to post by email, I received this error message:
Invalid request, please go back and try again.
Error Code: invalid_request
Error Message: Mismatch in redirect_uri.
I googled that error message, and found several Q & A links which all had the same bad news: The only solution is to uninstall Jetpack (deactivate and delete) and then re-install.
But I am hesitant to do that, because I have done a lot of work customizing the many features of WP, including Jetpack widgets, sharing, etc,
If I delete Jetpack, don't I lose all that work? WP Move has a backup functionality which I used before moving to the new subdomain. And I know that WP is capable of exporting and importing some of its data such as posts.
But is there a way I can back up all the options and settings and widgets that belong to Jetpack, and restore them after the reinstall?
BTW, if it is true that uninstall/reinstall is the only way out, then that is a major bug. I hope the developers of Jetpack have fixing it on their to-do list.