Guest user can't access Client Side Assets resources in SharePoint App Catalog site
When using third party web part or custom web part, there is a property named includeClientSideAssets that push resources to Client Site Assets library of the SharePoint App catalog site. Anytime a user is using one of those web parts, he will retrieve resources from this centralized area. This Client site assets library is hidden and is at least read-only for every member of your organization but it is not accessible to external user. As consequence external users are getting errors like below. [SPLoaderError.loadComponentError]: Failed to load component "544c1372-42df-47c3-94d6-017428cd2baf" (pnpSearchResultsWebPart). Original error: Failed to load path dependency "SearchResultsWebPartStrings" from component "544c1372-42df-47c3-94d6-017428cd2baf" (pnpSearchResultsWebPart). Original error: Error loading https://component-id.invalid/544c1372-42df-47c3-94d6-017428cd2baf_4.1.0/SearchResultsWebPartStrings Unable to load script https://mytenant.sharepoint.co...