Hi KhalidAlRehaily-3347,
Does anyone else have the same issue?
Does this issue only happen on .pdf files?
Do you try the desktop client and if this issue still exists?
I have some confusions to confirm with you. According to your image, it seems this error happens on OneDrive. While the files shared in channels are saved in SharePoint site. So, what is your scenario?
Sharing in Teams is based on the settings configured in SharePoint and OneDrive, so whatever you set up for SharePoint and OneDrive will control sharing in Teams as well. For more information about how to configure sharing in OneDrive and SharePoint, please refer to this article: https://learn.microsoft.com/en-us/MicrosoftTeams/sharing-files-in-teams#configure-sharing-in-onedrive-and-sharepoint.