diff --git a/apps/api/src/lib/common.ts b/apps/api/src/lib/common.ts
index a55aa1c7b..3f09478ca 100644
--- a/apps/api/src/lib/common.ts
+++ b/apps/api/src/lib/common.ts
@@ -715,7 +715,7 @@ export async function stopTraefikProxy(
 }
 
 export async function listSettings(): Promise<any> {
-	return await prisma.setting.findFirst({});
+	return await prisma.setting.findUnique({ where: { id: '0' } });
 }
 
 export function generateToken() {
diff --git a/apps/api/src/routes/api/v1/settings/handlers.ts b/apps/api/src/routes/api/v1/settings/handlers.ts
index c835f3020..4b2af55eb 100644
--- a/apps/api/src/routes/api/v1/settings/handlers.ts
+++ b/apps/api/src/routes/api/v1/settings/handlers.ts
@@ -2,7 +2,7 @@ import { promises as dns } from 'dns';
 import { X509Certificate } from 'node:crypto';
 import * as Sentry from '@sentry/node';
 import type { FastifyReply, FastifyRequest } from 'fastify';
-import { asyncExecShell, checkDomainsIsValidInDNS, decrypt, encrypt, errorHandler, isDev, isDNSValid, isDomainConfigured, listSettings, prisma, sentryDSN, version } from '../../../../lib/common';
+import { asyncExecShell, checkDomainsIsValidInDNS, decrypt, encrypt, errorHandler, getDomain, isDev, isDNSValid, isDomainConfigured, listSettings, prisma, sentryDSN, version } from '../../../../lib/common';
 import { AddDefaultRegistry, CheckDNS, CheckDomain, DeleteDomain, OnlyIdInBody, SaveSettings, SaveSSHKey, SetDefaultRegistry } from './types';
 
 
@@ -68,10 +68,26 @@ export async function saveSettings(request: FastifyRequest<SaveSettings>, reply:
             DNSServers,
             proxyDefaultRedirect
         } = request.body
-        const { id } = await listSettings();
+        const { id, previewSeparator: SetPreviewSeparator } = await listSettings();
         if (numberOfDockerImagesKeptLocally) {
             numberOfDockerImagesKeptLocally = Number(numberOfDockerImagesKeptLocally)
         }
+        if (previewSeparator == '') {
+            previewSeparator = '.'
+        }
+        if (SetPreviewSeparator != previewSeparator) {
+            const applications = await prisma.application.findMany({ where: { previewApplication: { some: { id: { not: undefined } } } }, include: { previewApplication: true } })
+            for (const application of applications) {
+                for (const preview of application.previewApplication) {
+                    const { protocol } = new URL(preview.customDomain)
+                    const { pullmergeRequestId } = preview
+                    const { fqdn } = application
+                    const newPreviewDomain = `${protocol}//${pullmergeRequestId}${previewSeparator}${getDomain(fqdn)}`
+                    await prisma.previewApplication.update({ where: { id: preview.id }, data: { customDomain: newPreviewDomain } })
+                }
+            }
+        }
+
         await prisma.setting.update({
             where: { id },
             data: { previewSeparator, numberOfDockerImagesKeptLocally, doNotTrack, isRegistrationEnabled, dualCerts, isAutoUpdateEnabled, isDNSCheckEnabled, DNSServers, isAPIDebuggingEnabled }
diff --git a/apps/ui/src/routes/settings/coolify.svelte b/apps/ui/src/routes/settings/coolify.svelte
index 5356849b7..46f4ac17a 100644
--- a/apps/ui/src/routes/settings/coolify.svelte
+++ b/apps/ui/src/routes/settings/coolify.svelte
@@ -166,12 +166,15 @@
 			}
 			if (proxyDefaultRedirect !== settings.proxyDefaultRedirect) {
 				await post(`/settings`, { proxyDefaultRedirect });
+				settings.proxyDefaultRedirect = proxyDefaultRedirect;
 			}
 			if (numberOfDockerImagesKeptLocally !== settings.numberOfDockerImagesKeptLocally) {
 				await post(`/settings`, { numberOfDockerImagesKeptLocally });
+				settings.numberOfDockerImagesKeptLocally = numberOfDockerImagesKeptLocally;
 			}
 			if (previewSeparator !== settings.previewSeparator) {
 				await post(`/settings`, { previewSeparator });
+				settings.previewSeparator = previewSeparator;
 			}
 			if (minPort !== settings.minPort || maxPort !== settings.maxPort) {
 				await post(`/settings`, { minPort, maxPort });
@@ -422,7 +425,7 @@
 				</div>
 				<div class="grid grid-cols-2 items-center">
 					<div>
-						Preview Domain Seprator
+						Preview Domain Separator
 						<Explainer
 							position="dropdown-bottom"
 							explanation="The separator used in the PR/MR previews.<br><br>For example if you set it to: <span class='text-yellow-400 font-bold'>-</span><br> the preview domain will be like this: <br><br><span class='text-yellow-400 font-bold'>PRMRNumber-yourdomain.com</span><br><br>The default is: <span class='text-yellow-400 font-bold'>.</span><br>so the preview domain will be like this: <br><br><span class='text-yellow-400 font-bold'>PRMRNumber.yourdomain.com</span>"
@@ -430,6 +433,7 @@
 					</div>
 					<input
 						class="w-full"
+						required
 						bind:value={previewSeparator}
 						readonly={!$appSession.isAdmin}
 						disabled={!$appSession.isAdmin}