Search not working on Sharepoint2019 public facing site

Question

I have SharePoint 2019 on premise communication site which manages the public facing site. My search is working on on-premise site but it shows the error message which says

Access to XMLHttpRequest at 'On premise site' from origin 'public facing site' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

I assume that I need to put the rules and add allow content origin policy in the web.config file inside the <system.webServer>. What and how should I add the allow customHeaders? The existing customHeaders

<add name="X-Content-Type-Options" value="nosniff" />
<add name="X-MS-InvokeApp" value="1; RequireReadOnly" />

Should I delete it? I tried adding the following but does not work for me.

<system.webServer>
   <httpProtocol>
     <customHeaders>
         <add name="Access-Control-Allow-Headers" value="Origin, X-Requested-With, Content-Type, Accept" />
         <add name="Access-Control-Allow-Methods" value="POST,GET,OPTIONS,PUT,DELETE" />
     </customHeaders>
   </httpProtocol>
        <rewrite>            
            <outboundRules>
                <clear />                
                <rule name="AddCrossDomainHeader">
                    <match serverVariable="RESPONSE_Access_Control_Allow_Origin" pattern=".*" />
                    <conditions logicalGrouping="MatchAll" trackAllCaptures="true">
                        <add input="{HTTP_ORIGIN}" pattern="(http(s)?://((.+\.)?domain1\.com|(.+\.)?domain2\.com|(.+\.)?domain3\.com))" />
                    </conditions>
                    <action type="Rewrite" value="{C:0}" />
                </rule>           
            </outboundRules>
        </rewrite>
 </system.webServer>

Answer 1

Your SharePoint Communication site is either trying to send multiple Access-Control-Allow-Origin headers, or one Access-Control-Allow-Origin header with multiple values. I believe none is allowed.

So the idea is you need to fix your SPConfig so that it only

• sends this header once
• specifies a single value

Go to SP Admin Center → App Management → Manage Services on Server : Stop the Request Management Service