Intelligent Indexing issue

Email PDFs can be imported to the trays, but below is the message I get when attempting to run the indexing feature.

What is the port required for Intelligent Indexing?   If I can get this information I can verify it is accessible prior to opening a ticket with DocuWare.
Email PDFs can be imported to the trays, but below is the message I get when attempting to run the indexing feature.

What is the port required for Intelligent Indexing?   If I can get this information I can verify it is accessible prior to opening a ticket with DocuWare.

DW returning: The last attempt with intelligent indexing service failed, a connection to the service could not be established

There is a nice list of the used ports listed in this Knowledge Base article:
https://support.docuware.com/en-us/knowledgebase/article/KBA-34951

However, Intelligent Indexing works over http/https, so use Your preferred tools to check layers 2/3 for connections to the url of the Intelligent Indexing Service, which you can find in the intelligent indexing module of the web configuration.

It might well be a DNS issue, so You may want to verify the the URL can be properly resolved.