Customer receives error at shopping cart when trying to complete (charge) order – error was something like “Error processing payment, please try again later”.
WooCommerce > Status > Logs > woocommerce-square-sync-XXX
log shows repeated:
Renewing expired token error - Internal Server Error 500 from https://connect.woocommerce.com/renew/square
Solution:
Disconnect Square from WooCommerce in Dashboard > WooCommerce > Settings > Integrations, and then reconnect to Square.
note: Upon reactivation, all Square settings, including log email address, were maintained. I think it was literally 3 clicks since I was already logged in to the Square account in the same browser.