Hi Mark,
It sounds like you may be running into a security change that Salesforce rolled out with regards to guest users. Can you take a look at this thread, and follow up there if you have a question?
https://community.skuid.com/t/salesforce-s-spring-20-release-changes-regarding-guest-users-starting-march-1-2020
Specifically for scenarios where this change impacts functionality using file uploads, here’s a bit of info that’s relevant:
Salesforce’s change also impacts Skuid’s File Upload component for site guest users. The Skuid Product Engineering team is working on a product change to restore the ability for Guest Users to use Skuid’s File Upload component to upload attachments to records. This change will be available in 11.2.30 and 12.2.14.
