[SalesForce] Insufficient privileges in Send Email

In order to change the link URL for the New Email button, you have to use a Javascript hack. Create a new "narrow" Homepage Component (really a Sidebar component, but SFDC calls them Homepage components) and paste the following code in (be sure to check off Show HTML first, so that this is entered as code, not as text)

<div id="remove-shortcut-id">
Click "Show HTML" to see hidden javascript code.<br/>
<b>DO NOT SAVE UNLESS JAVASCRIPT IS VISIBLE</b> or else that code will be erased.
</div>

<script type="text/javascript"><!--
function changeNewEmailQuery() {
    var PARAMETERS_TO_ADD = 'p26=add_it_here&other=if_another_one';
    var cid = window.location.pathname.replace('\/', '');
    if (cid.indexOf('500') != 0) return;
    var newEmailBtn = document.getElementsByName("newEmail");
    if (newEmailBtn[0] && newEmailBtn[0].query_fixed == false) {
        var btn = newEmailBtn[0];
        var fn = btn.onclick.toString()
        var navUrl = fn.match(/navigateToUrl\('([^']*)'.*/)[1];
        navUrl = navUrl + "&" + PARAMETERS_TO_ADD;
        btn.onclick = function (event) { navigateToUrl(navUrl, null, 'newEmail'); };
        btn.query_fixed = true;
    }
}
/* Run immediately on page load and queue for second run after related lists load */
changeNewEmailQuery();
setTimeout('changeNewEmailQuery();', 100);
/* hide this component */
document.getElementById('remove-shortcut-id').parentElement.style.display = 'none';
--></script>

Save this component and add it to your Homepage layout as a narrow column. The code will run on each page load, and whenever it sees the NewEmail, it will edit the query string.

(Fixed doublequote issue)

Your requirement is achievable.

1. Create a unique Case Origin let's say TestEmailRouting and assign this origin whenever Email-to-Case is getting created for that routing address.

2. Create a Process builder process on Case object, during case creation and update Case record as follows:

   • Contact Id to BLANK

   • CaseOrigin to Email (i.e. from TestEmailRouting to Email)

with a criteria CaseOrigin equals TestEmailRouting

You can also handle this with a recordtype.

3. Create a flow which will search for correct Contact based on emailId and division and assign the Contact to the Case. Call this flow from process builder.