diff --git a/client/src/campaigns/Status.js b/client/src/campaigns/Status.js
index 6cfd8b92..ef1c9617 100644
--- a/client/src/campaigns/Status.js
+++ b/client/src/campaigns/Status.js
@@ -72,7 +72,7 @@ class PreviewForTestUserModalDialog extends Component {
                 });
 
                 const accessToken = result.data;
-                window.open(getSandboxUrl(`campaigns/rss-preview/${campaignCid}/${listCid}/${subscriptionCid}`, accessToken, {withLocale: true}), '_blank');
+                window.open(getSandboxUrl(`cpgs/rss-preview/${campaignCid}/${listCid}/${subscriptionCid}`, accessToken, {withLocale: true}), '_blank');
 
             } else if (entity.type === CampaignType.REGULAR) {
                 window.open(getPublicUrl(`archive/${campaignCid}/${listCid}/${subscriptionCid}`, {withLocale: true}), '_blank');
diff --git a/locales/en-US/common.json b/locales/en-US/common.json
index 6428b301..fa23af49 100644
--- a/locales/en-US/common.json
+++ b/locales/en-US/common.json
@@ -157,7 +157,7 @@
   "campaign_plural": "Campaigns",
   "contentOfTheSelectedCampaignWillBeCopied": "Content of the selected campaign will be copied into this campaign.",
   "renderUrl": "Render URL",
-  "ifAMessageIsSentThenThisUrlWillBePosTed": "If a message is sent then this URL will be POSTed to using Merge Tags as POST body. Use this if you want to generate the HTML message yourself.",
+  "ifAMessageIsSentThenThisUrlWillBePosTed": "If a message is sent then this URL will be POSTed to using Merge Tags as POST body. Use this if you want to generate the HTML message yourself. Example: http://www.example.com/foo",
   "deletingCampaign": "Deleting campaign ...",
   "campaignDeleted": "Campaign deleted",
   "formCannotBeEditedBecauseTheCampaignIs": "Form cannot be edited because the campaign is currently being sent out. Wait till the sending is finished and refresh.",
diff --git a/server/app-builder.js b/server/app-builder.js
index c2a285a6..a6c1a984 100644
--- a/server/app-builder.js
+++ b/server/app-builder.js
@@ -275,7 +275,7 @@ async function createApp(appType) {
         useWith404Fallback('/files', files);
     }
 
-    useWith404Fallback('/campaigns', await campaigns.getRouter(appType));
+    useWith404Fallback('/cpgs', await campaigns.getRouter(appType)); // This needs to be different from "campaigns", which is already used by the UI
 
     useWith404Fallback('/mosaico', await sandboxedMosaico.getRouter(appType));
     useWith404Fallback('/ckeditor', await sandboxedCKEditor.getRouter(appType));
diff --git a/server/lib/message-sender.js b/server/lib/message-sender.js
index fa5abfa7..ec26d3e0 100644
--- a/server/lib/message-sender.js
+++ b/server/lib/message-sender.js
@@ -200,14 +200,16 @@ class MessageSender {
                 form[key] = mergeTags[key];
             }
 
+            const sourceUrl = campaign.data.sourceUrl;
+
             const response = await request.post({
-                uri: campaign.sourceUrl,
+                uri: sourceUrl,
                 form,
                 resolveWithFullResponse: true
             });
 
             if (response.statusCode !== 200) {
-                throw new Error(`Received status code ${httpResponse.statusCode} from ${campaign.sourceUrl}`);
+                throw new Error(`Received status code ${httpResponse.statusCode} from ${sourceUrl}`);
             }
 
             html = response.body;