Syntex Error

Looks like you're missing a closing curly bracket. Try this one:

when HTTP_REQUEST {

     tell server not to compress response
    HTTP::header remove Accept-Encoding

     disable STREAM for request flow
    STREAM::disable
     redirect autodiscover requests to autodiscover site
    if { [string tolower [HTTP::path]] equals "/autodiscover/autodiscover.xml" } {

        HTTP::respond 301 "Location" "https://autodiscover.domainnet.us/autodiscover/autodiscover.xml"
         redirect http://domainnet.us to https://www.domainnet.us along with any uri

    } elseif { [string tolower [HTTP::host]] equals "domainnet.us" } {
            HTTP::respond 301 "Location" "https://www.domainnet.us[string tolower [HTTP::uri]]"
    } elseif { [string tolower [HTTP::uri]] starts_with "/health-blog/" } { 
        set uri [string map {"/health-blog/" "/health-byte/"} [HTTP::uri]]
        HTTP::redirect "https://www.domainnet.us$uri"
        log local0. "outgoing URI = $uri"
    }


    switch -glob [string tolower [HTTP::path]] {
        "/en/sitemap.xml*" { 
                 set uri1 "/en-sitemap.xml" 
                HTTP::uri "/en-sitemap.xml" 
                log local0. "Find String= /en/sitemap.xml and Replaced uri: [HTTP::uri]" 
        }
        "/ar/sitemap.xml*" { 
             set uri1 "/ar-sitemap.xml"
            HTTP::uri "/ar-sitemap.xml"
            log local0. "Find String= /ar/sitemap.xml and Replaced uri: [HTTP::uri]"
        }
    }
}   


when HTTP_RESPONSE {

     catch and replace redirect headers
    if { [HTTP::header exists Location] } {
        HTTP::header replace Location [string map {"http://" "https://"} [string tolower [HTTP::header Location]]]

    } 

     only look at text data
    if { [HTTP::header Content-Type] contains "text" } {

         create a STREAM expression to replace any http:// with https:// for NET and preprod
        STREAM::expression {@http://s5.donet.us@https://s5.donet.us@ @http://s1.donet.us@https://s1.donet.us@ @http://s2.donet.us@https://s2.donet.us@ @http://s3.donet.us@https://s3.donet.us@ @http://s4.donet.us@https://s4.donet.us@ @preprod.donet.us@www.domainnet.us@ @http://www.domainnet.us@https://www.domainnet.us@}



         enable STREAM
        STREAM::enable
    }
}