In the UI api explorer all my endpoints have suddenly stopped working. Our web app still works which is calling the correct endpoints with the correct verbs.
But, for example the UI correctly identifies this method as a GET but when I click submit I get an exception saying 'Could not find method named Post(…) or Any(…) on Service …
The issue is your DataList Type inheriting Collection<DataInstance>, it’s not possible to serialize custom Types that inherits collections.
The only time this is supported is when defining a Request DTO that accepts a raw collection, but even that can’t support properties which isn’t serializable in any of our serialization formats.
Can you also remove any private repo packages from stand-alone repros, a nuget restore fails trying to download from https://nuget.pkg.github.com/MalumaSolutions/index.json.
Otherwise replacing DataList with List<DataInstance> seems to work without issue?
FYI you should leave package references as Version="6.*" instead of a mix of wildcard and Version="6.3.1" references as it’s easy for incompatible versions to be installed.