Replace All sites in the hub with Select sites and explicitly add all five sites; with only five direct associations, the incomplete automatic list is not explained by the documented 99-site limit.
Add the sites explicitly
- Open the hub home page and select Edit.
- Select the Sites web part, then Edit properties.
- Change All sites in the hub to Select sites.
- Under Sites associated with this hub, select all five sites. If necessary, search for each missing site by name.
- Republish the page and confirm that all five cards appear.
Microsoft documents Select sites as the supported alternative to automatic hub-site selection.^1^
This also provides a useful diagnostic:
- The three missing sites can be selected and appear after publishing: their hub associations are recognized, while the automatic query is returning an incomplete result. Keep the explicit selection as the immediate workaround.
- The sites cannot be found in Select sites: the problem is broader than the automatic display and should be escalated after the checks below.
What “All sites in the hub” should include
Microsoft describes associated-site content as rolling up to web parts whose source is All sites in the hub. The Sites web part supports a security-trimmed dynamic list of up to 99 sites, so five directly associated sites are well below its limit.^2^
The automatic option is documented for sites associated with the current hub.^1^ It is not documented as recursively including sites belonging to an associated child hub. Therefore, if any of the missing three sites are actually associated with a child hub rather than directly with this hub, use Select sites or add links to the hub navigation instead. A site can have only one direct hub association.^3^
If explicit selection also fails
Since reindexing, waiting more than 24 hours, “See all,” restarting, and access testing have already been tried, do not repeat those actions.
For each missing site, check only this additional search setting:
- Open the missing site.
- Go to Settings → Site settings → Search and offline availability.
- Verify Allow this site to appear in Search results is Yes.
Do not trigger another reindex—the setting is the relevant check here. Microsoft identifies disabled site search visibility as a cause of missing SharePoint Online search results.^4^
If that setting is already enabled and the sites remain unavailable in Select sites, this requires tenant-side investigation:
- Have a Microsoft 365 administrator check Microsoft 365 admin center → Health → Service health for a SharePoint Online advisory.
- If none applies, go to Support → Help and support and open a SharePoint Online support request.
- Include:
- The hub URL and the three missing site URLs.
- Screenshots of their hub associations in the SharePoint admin center.
- Whether each missing site appears under Select sites.
- Confirmation that the issue persists after more than 24 hours and reindexing was already attempted.
- Results from another user, if available.
Microsoft directs business administrators to check Service health and contact Microsoft support when an issue is not listed.^5^
References
- Use the Sites web part | Microsoft Support
- Planning your SharePoint hub sites
- Associate a SharePoint site with a hub site | Microsoft Support
- Search results missing in SharePoint Online
- [Personal account](https://support.microsoft.com/support/#microsoft-sales-support)