A form is missing or unstyled
Check the selected Form Picker value, published form status and published content page. Confirm the tag helper is registered in the applicable _ViewImports.cshtml. Check browser network requests for missing renderer CSS/JS and template images.
If a custom background covers another block, remove global/viewport styling and constrain it to the form root. See Theme integration.
Backoffice or entries return 401/403
Sign in through /umbraco/ and open MegaForm through the native section. Check the user's group access and MegaForm permissions. Modern backoffice API calls use the native authentication bridge; copying an internal iframe URL into a new unauthenticated tab does not grant access.
Distinguish “not signed in” from “signed in without permission”. Private attachment endpoints enforce entry access independently.
SQL choices are empty or writes fail
Check the named connection, provider syntax, real table/column names and permissions. Verify Value/Label mapping and parent dependency values. For Umbraco document lists, check the published root, Document Type filter, culture and page context.
For inserts, inspect the write mapping, required columns/defaults and recorded failure policy. Confirm the destination row rather than relying only on the thank-you screen.
C# is disabled or rejected
Check the server feature flag, deployed compiler, native administrator account and saved approval. Use Check syntax and Test run. Use C# 7.3-compatible syntax and ScriptHost, not obsolete ctx.Db/ctx.Http helpers. See C# scripting.
Upgrade checklist
Back up the database and private files. Test the new package on staging against the actual Umbraco runtime. Verify the section, builder, picker, live submit, entries, PDF download and configured integrations. Keep secrets and production licenses outside the redistributable package.
This site has been exercised on Umbraco 17.6.2/.NET 10. Other supported target versions need their own runtime checks before deployment.