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Salesforce OmniStudio: "An internal server error has occurred" on Proposal Actions, FlexCards, and Document Template Designer after Spring '26

Publish Date: Jul 16, 2026
Description

This article addresses OmniStudio components (proposal/actions pages, OmniStudio FlexCards, OmniScripts, and Document Template Designer) failing with a generic internal server error or with actions no longer appearing, following the OmniStudio security enhancements introduced in Winter '26 and Spring '26.

The exact on-screen message is "An internal server error has occurred An error has occurred while processing your request. The salesforce.com support team has been notified of the problem. If you believe you have additional information that may be of help in reproducing or correcting the error please contact Salesforce Support. Please indicate the URL of the page you were requesting, any error ID shown on this page, and any other related information." Some users instead see "You don't have access to this Apex class. Your Salesforce admin can help you with that" when opening Apex Access on their profile.

The security enhancements enable these feature flags by default starting February 2, 2026: AdvancedOmnistudioAccessCheck, ApexClassCheckForIP, ApexClassCheck, EnforceDMFLSAndDataEncryption, and EnableQueryWithFLS. 

When enabled, OmniStudio enforces object permissions, field-level security (FLS), and Apex class access for every running user (internal, Experience Cloud authenticated, and guest). Affected users are those whose profile or permission sets lack the required Apex class or FLS access; setup can differ between sandbox/UAT and production, which is why the same component works in one org and fails in another. 

Resolution

Work through the cause that matches your symptom.

Cause 1: OmniStudio components fail after the Spring '26 advanced access checks were enabled.

  • The flags AdvancedOmnistudioAccessCheck, ApexClassCheckForIP, ApexClassCheck, EnforceDMFLSAndDataEncryption, and EnableQueryWithFLS are enabled by default from February 2, 2026.
  • Identify the failing component's data source. Open the affected FlexCard, OmniScript, or Document Template and list every Salesforce object, field, and Apex class it reads or invokes.
  • Grant object and field access to the running user's profile or a permission set: go to Setup > Permission Sets > [select or create a permission set] > Object Settings > [each object used] and set Read for the objects and set Read for every field the component references under Field Permissions.
  • Grant Apex class access for every Apex class the component calls: go to Setup > Permission Sets > [your permission set] > Apex Class Access > Edit, move each required class to Enabled Apex Classes, then click Save.
  • Assign the permission set to the affected users: Setup > Permission Sets > [your permission set] > Manage Assignments > Add Assignments.
  • For Experience Cloud authenticated users, apply steps 3-5 to the site's member permission sets. For guest users, create a permission set with Read-only object and field access and configure sharing rules to expose the required records for anonymous access.

Cause 2: Proposal or component actions disappeared after the release (no error, buttons missing).

  • The action buttons are hidden because the running user fails the new Apex class or FLS check for the action's data map. Follow Cause 1 steps 2-5 for the objects, fields, and Apex classes referenced by each missing action.
  • Re-activate the affected OmniStudio component so it re-evaluates access: open the FlexCard or OmniScript in the designer and click Activate.

Cause 3: "You don't have access to this Apex class" when editing Apex Access, or setup differs between UAT and Production.

  • Compare the working org and failing org. In the working org, open Setup > Profiles > [profile] > Enabled Apex Class Access (or the assigned permission set) and record the enabled classes.
  • In the failing org, add the identical Apex classes via Setup > Permission Sets > [permission set] > Apex Class Access > Edit, or Setup > Profiles > [profile] > Apex Class Access > Edit. Use a permission set rather than direct profile edits when the profile Apex Access page returns an error.

Cause 4: Document Generation from OmniScript fails with a limit or size error on large data maps.

  • Reduce the data map payload so it stays within Apex governor and heap limits: request only the specific tags your template needs instead of broad entity-level tags.
  • Split large document generation into smaller batches or paginate the source records.

Confirm the issue is resolved by reopening the affected proposal page, FlexCard, or Document Template Designer as the previously failing user: the page loads, all action buttons appear, and no internal server error is displayed.

Knowledge Article Number

005389123

 
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Salesforce Help | Article