Hi Christopher, 

I see the domain warning when my gateway is set to Round Robin. However, I'm not able to replicate an issue with the Save button. What change did you make to the gateway? Do you perhaps have an invalid fields that need to be fixed first? (You can find out by placing your cursor in the Server Address field and tabbing through all fields on the page. If any inputs are invalid, this will force the red validation error to appear.)

Ah, yes, the "Enable SmarterMail Gateway Mode" => "SmarterMail URL" option says that https://xxxxxx is not a valid domain name, even though it's asking for a URL, not a domain name, if I remove the https:// prefix it works fine, but this now means that SM is communicating with the gateway without HTTPS.

Hi,

I have similar problem on incoming gateway configuration (SM 17), I cannot edit gateway until change “Smartermail URL” to something like "mydomain.com" so I cannot use HTTPS for Smartermail URL. Also, in delivery logs there’s no Spam check results so I cannot tell whether spam check works.

I've reported URL field as an addition to my incoming gateway issue here:

EDIT: I'm wondering are you using incoming gateways as a Domain Forward?

Yeah, it doesnt accept "http" prefix at all, only a hostname without the protocol.

Webio, I'm using incoming gateways as a Domain Forward.
Can you check your delivery logs for spam check results?

Are you using v17 incoming gateway with Domain Forward, disabled SmarterMail Gateway mode and enabled SMTP Verification? I've made some tests today (I've upgraded again one of my v16 incoming gateways, disabled smartermail gateway mode, enabled SMTP Verification, Domain set to All Domains except where I added one random domain - IMHO there should be third option All Domains - and in this configuration no checks are being made.