Troubleshooting and support

1.1 Common issues

• Authentication pop-up blocked: allow pop-ups for the platform domain and retry Connect. • Query errors: the server returns an OperationOutcome; review the message for unsupported parameters. • Slow results: reduce _count, narrow filters, avoid broad include/revinclude. • No results: remove overly strict filters or confirm the server has data for your study tag/patient id.

1.2 Current limitations

The FHIR Viewer is evolving. The following limitations describe current behavior and supported functionality.

Query limitations • The viewer supports read‑only, GET‑based FHIR queries only. You cannot run POST operations or system‑level interactions (for example, $validate, $export, or _history queries). • To prevent excessively large responses, the _count parameter is capped at 10,000 results per query. • Due to the highly nested and interconnected nature of FHIR data, complex queries may return no results or results that are difficult to interpret.

• FHIR recommends using _include and _revinclude with caution, especially when traversing three or more resource relationships. _revinclude queries often return much larger result sets than _include, and many servers impose limits that may truncate or restrict responses. • For best results, start with simple, resource‑focused queries and layer in includes or additional filters incrementally. • The viewer currently supports Bundle‑based responses only. Non‑Bundle responses may fail to render or return errors.

View limitations • When a query returns more than 200 resources, the Table (flattened) view is disabled. • The JSON view remains fully available, and no information is lost. • When you export results, the viewer flattens all returned values and writes the complete dataset to a TSV file in your Project, even if the table view is restricted in the UI.

Functional limitations • You cannot currently save your queries or view history in the viewer. This functionality is planned for a future iteration. • You cannot create a new Project from within the viewer, but you can export results to an existing Project.

• If the Project you want does not yet exist, you can create it in a separate CAVATICA tab. The new Project will appear in the Export dialog without affecting your current query results. • Export performance and stability may degrade for very large datasets, especially when multiple export jobs run at the same time. • Advanced cohort‑building capabilities and AI‑assisted features are not currently available in this version of FHIR Viewer.

1.3 When contacting support

Most issues you encounter while running queries - especially query syntax, unsupported parameters, or server constraints will return a server‑side error response (for example, an OperationOutcome) directly in the viewer. In many cases, you can resolve these issues by reviewing the error message and editing your query accordingly, without needing to wait for support. If the issue persists, no clear diagnosis is returned, or the behavior is unexpected, contact support and include the following information to help speed up resolution: • Server name (Kids First / other) • Exact query string you ran • Timestamp (approx.) • Screenshot of inline banner or JSON error response • Whether the issue appears in JSON view, Table view, or both