SharePoint Incoming Email functionality not working

If the file is copied to the Queue folder instead of the Drop folder, open the file and check the content, probably this would be because the recipient is not recognised. This means that the email domain that we have set up is not correct. Check the domain name and try this procedure again.

Check for the email address of list/library is correct. If you send email to other libraries, will the issue occur?

Ensure that SMTP server is running.

Make sure Microsoft SharePoint Foundation Incoming E-Mail timer job is running successfully.

Make sure the SharePoint Timer service account have permission on drop folder.

Restart SharePoint Timer service.

References:

https://guruandi.wordpress.com/2012/05/03/sharepoint-incoming-email-not-working/

https://bernado-nguyen-hoan.com/2013/06/18/solving-sharepoint-2013-incoming-mails-stuck-in-drop-folder/

If this content DB was migrated from another server, it may be that the email configurations need to be refreshed. See https://www.sharepointdiary.com/2013/08/fix-incoming-emails-not-working-issue-in-migration.html for more details, but the script offered there (and copied below) worked well for me:

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue #Get All Site Collections of the given web application $SiteCollections = Get-SPWebApplication "https://YourSharePointWebApplicationGoesHere" | Get-SPSite -Limit All #Iterate through Each site collection ForEach ($site in $SiteCollections) { #Refresh Incoming Email settings $site.RefreshEmailEnabledObjects() #Write Ouput message Write-Host "Processed: $($site.rootweb.url)" #Dispose the Site object $site.Dispose() } 

One other necessary step is that the service account running the SharePoint Timer Service needs access to the mail drop folder. The default path is C:\inetpub\mailroot\Drop