Power Pages Liquid and portal errors

Power Pages sites are Dataverse-backed and templated with Liquid, Shopify's templating language, so most errors either come from Liquid syntax and object references, or from the table permission and web role model that decides what an anonymous or signed-in visitor can actually see and do against Dataverse.

"Liquid error: Unknown tag" / "Liquid syntax error"

Symptom. A page renders a raw error message instead of the intended content, visible to whoever is viewing the page (or hidden from anonymous visitors, depending on site settings).

Cause. A Liquid tag is misspelled, uses a construct Power Pages' Liquid implementation doesn't support (it's a subset, not the full Shopify Liquid feature set), or references a variable that was renamed or removed elsewhere on the page.

Fix. Check the exact tag name and syntax against Power Pages' supported Liquid reference, and preview the page in the design studio (which surfaces more diagnostic detail than a live site does) while making the fix.

Prevention. Keep complex Liquid logic in as few, well-tested templates as possible rather than duplicating similar logic across many pages — a syntax mistake in one shared template is one fix, while the same mistake copy-pasted across a dozen pages is a dozen fixes found one at a time as visitors report them.

"You do not have permission to access this page" on a page that should be public

Symptom. A page that's meant to be visible to anonymous visitors shows a permission-denied message.

Cause. The page's associated web page access control (a web role restriction) doesn't include an "Anonymous Users" entry, or the site setting controlling anonymous access is misconfigured.

Fix. Check the page's web-role-based access control list and confirm anonymous access is explicitly granted where intended — Power Pages defaults toward restricting access, so a page needs an explicit grant, not just the absence of a restriction.

Prevention. Maintain a simple access matrix (which page, which web roles, anonymous or not) as a design artefact before building pages, so access control is a deliberate decision reviewed at launch rather than discovered through a visitor's bug report.

Form submission fails silently or with "An error has occurred"

Symptom. A visitor submits a Basic Form or an Advanced Form and gets a generic failure instead of the expected confirmation.

Cause. Most commonly a table permission gap (the web role can see the form but lacks Create or Write permission on the underlying table), a required field validation failure the form isn't surfacing clearly, or a business rule or plug-in on the Dataverse side rejecting the write for a reason the portal doesn't translate into a friendly message.

Fix. Reproduce the submission as a test user with the same web role, check the browser's network tab for the actual API response, and check Dataverse-side plug-in trace logs (via XrmToolBox's Plugin Trace Viewer) if a plug-in is involved in the rejection.

Prevention. Test every form against a test account holding exactly the web roles a real visitor would have — testing as a system administrator hides every table-permission gap a real visitor will hit.

Styling or JavaScript changes not appearing after publish

Symptom. A change to a web template, CSS, or a portal's custom JavaScript doesn't show up on the live site even after a clear browser cache.

Cause. Power Pages caches content aggressively for performance; a change needs to actually publish (not just save) and the site's content delivery cache needs to expire or be explicitly cleared.

Fix. Use the "Clear Cache" action available from the Power Pages management app or design studio after publishing, rather than assuming a save alone propagates immediately.

Prevention. Build a habit of publish-then-clear-cache-then-verify as one deliberate sequence for content changes, especially before a scheduled go-live, so a caching lag isn't mistaken for a failed deployment at the worst moment.

Where to go next

Table permission design specifically is covered in Power Pages security in depth; the templating side in Power Pages Liquid templating. For the portal's relationship to Dataverse search, see Power Pages with Dataverse search.