I am getting an error message when I try amending or adding a site items. Been ok for years but stopped working today.
Hey @Henhouseart, welcome to the Seller Community.
I'm sorry to hear that - what is the error message saying? Please attach a screenshot here if possible.
I'll also add some general troubleshooting steps here, but if they don't resolve the issue, please provide a little more detail here so that we can try to get this resolved as soon as possible.
Troubleshooting steps:
Square Community
Square Products