External Sharing with Communication sites gives 403 error

[Jeremy Hancock]

I am trying to share a communications site with external users. Sharing is enabled and the user has permissions to the site. They can see and work with the site but they are prompted for credentials during the page load. The site icons don't display. I get a 403 error in the network log.

https://<tenant>.sharepoint.com/search/_api/search/query?querytext=%27*%27&ClientType=%27CommSiteSearch%27&Properties=%27ClientFunction%3APersonalRelevanceContext%2CFetchPersonalRelevanceContext%3Atrue%27&EnableQueryRules=false&ProcessBestBets=false&BypassResultTypes=true&ProcessPersonalFavorites=false&SourceId=%278413cd39-2156-4e00-b54d-11efd9abdb89%27&suxrid=ms-oil-datasource-spopersonalcontext

If I try to go to that URL with the external user, I get;

<m:error xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">

<m:code>-2147024891, System.UnauthorizedAccessException</m:code>

<m:message xml:lang="en-US">

Access denied. You do not have permission to perform this action or access this resource.

</m:message>

</m:error>

How can I resolve this so the user doesn't get prompted and they have the necessary access.

Thanks

[#2]

There is a known issue with sharing modern team sites with external users that I think is also affecting communication sites since the error you are having is essentially the same. The SharePoint team is supposed to be working on fixing this, but I don't have an idea of current status

[#3]

I have spent some time with Microsoft Support. There seems to be a few issues.

1. The default logo can't be seen by external users. If you add a custom logo then it will appear for the external user.

2. The external user cannot see the images for news articles in a modern site unless they have read access to the root site collection.

3. Roll-up of news articles in the hub site is not working for external users. Support are looking into this issue.

[#4]

The hover cards for people is the biggest one since sharing folders and what not or accessing libraries cause he prompts due to those trying to render and making authentication boxes show up.

Anyway. If you hide comments option on a modern page. And don’t use people web part. Or if you have pages with modified by or created by fields showing you’ll get prompts. If you remove these from default views and pages then they won’t come up. Still waiting for fixes on this it’s been going on two months.