Custom SRV record not working

Hello! I am trying to add an SRV record to a client’s domain as requested by their IT person. It is supposed to help them with Outlook functionality.

Here is the info he provided:

Record Type: SRV
Priority: 0
Weight: 0
Port: 443

For one, I don’t see a place on the DNS records page for port, so I added it to the end of

Here is what I have:

I keep getting that error ‘domain is blank’ but I am not sure what to do. That address does exist, it is just secure. Why would that matter? I have tried it without the port on the end and still had no luck.

Any advice would be great. Thanks!