After filling the shipping information in the first step of checkout, I click on the “Continue” button and the site stops responding. The spinning wheel appears but it is not possible to click on anything else.
It seems the cause of this issue is a “uffef” character inserted somehow in a file. See image attached to see more information obtained from the page inspector in Firefox.
How can I find the file to edit so I can remove that character?
This issue occurs in a secondary store within the same magento installation. The main store is working fine.