> For the complete documentation index, see [llms.txt](https://docs.ngsurvey.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ngsurvey.com/installation-setup/system-settings/mailing-server/iis-smtp-exchange-server-1.md). # Postmark Enables ngSurvey to use PostMark's email sending API. ## 🔅 Postmark properties * **`Server API token`**is the token provided by your Postmark account for sending emails. * **`Webhook handler`**can be used and set within your Postmark account to track bounced and invalid emails. * **`Restrict globally to one sender`** if enabled it allow us to specify one email and name that will be used for all email sending processes within ngSurvey. If activated ngSurvey will only use the email specified and will not use anymore the user account email and wont allow the user to enter any email for any of the email features like campaigns, tasks. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation by asking a question. Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters: ``` GET https://docs.ngsurvey.com/installation-setup/system-settings/mailing-server/iis-smtp-exchange-server-1.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.