IIS URL rewrite not working via search engines

I have written a simple url rewrite rule for my website hosted in IIS 10. It works perfectly without any issue.

However, there is a strange behavior. When I write url directly in the browser rule works fine, but if I search url in Google/Bing and then click the url on search page, rule didn't trigger.

I looked into Insights didn't find any relevant information.

Here is the rule -

<rule name="PROD Rule" enabled="true" stopProcessing="true">
      <match url="(.*)" />
      <conditions>
        <add input="{HTTP_HOST}" pattern="^myweb\.com$" />
      </conditions>
      <action type="Redirect" url="https://www.mywebsite.com/{R:0}" redirectType="Permanent" />
</rule>

Writing url directly in browser -

myweb.com redirects to https://www.mywebsite.com/

Searching url in search engine Google/Bing and then clicking url on search result page -

myweb.com stays at myweb.com

I was expecting that the rules should trigger whenever request reaches IIS irrespective of source of origin.

Solution

So it turns out to be not a problem related to search engines. Instead it was just a missed case by rewrite rules I have written.

Existing rules were expecting myweb.com as input and correctly redirecting them to https://www.mywebsite.com/

However, when I search same url on search engine and click on them. Url send to server is NOT myweb.com instead www.myweb.com

Here is an update rules which worked -

<rule name="PROD Rule" enabled="true" stopProcessing="true">
    <match url="(.*)" />
    <conditions logicalGrouping="MatchAny">
        <add input="{HTTP_HOST}" pattern="^myweb\.com$" />
        <add input="{HTTP_HOST}" pattern="^threeinsure\.com$" />
    </conditions>
    <action type="Redirect" url="https://www.mywebsite.com/{R:0}" redirectType="Permanent" />
</rule>