redirection from non-www to www and http to https in IIS - redirect

Question

I am trying to redirect from non-www site to www and also from http to https.
Http to https works well, but non-www to www shows a page not found error.
This is my configuration:
<rules>
<clear />
<rule name="non-www to www" stopProcessing="true">
<match url="(.*)" />
<conditions logicalGrouping="MatchAny" trackAllCaptures="false">
<add input="{HTTP_HOST}" pattern="^mydomain.com$" />
</conditions>
<action type="Rewrite" url="https://www.{HTTP_HOST}{REQUEST_URI}" appendQueryString="false" />
</rule>
<rule name="http to https" patternSyntax="Wildcard" stopProcessing="true">
<match url="*" />
<conditions logicalGrouping="MatchAny" trackAllCaptures="false">
<add input="{HTTPS}" pattern="OFF" />
</conditions>
<action type="Redirect" url="https://{HTTP_HOST}{REQUEST_URI}" appendQueryString="false" />
</rule>
</rules>
What is going on? I have tried several variants for non-www to www, all from sites found in google, but non worked.
Jaime

Answer 1

Copied from the comment with more explanation.
The action should be set to Redirect instead of Rewrite, because you do want search engines to show www links, and then your site must issue 301 redirection to their bots.
Even if you sometimes want Rewrite, the url must be a relative path to the same site. If rewriting to another site (like the one you used above), then ARR is required with proxy mode. Otherwise, IIS naturally returns 404 errors.
However, rewriting does not change URLs in browser address bar, so it also has no effect on search engine bots.
Reference