diff --git a/apps/server/src/integrations/environment/environment.service.ts b/apps/server/src/integrations/environment/environment.service.ts
index d9ef01abb..abee1966f 100644
--- a/apps/server/src/integrations/environment/environment.service.ts
+++ b/apps/server/src/integrations/environment/environment.service.ts
@@ -134,6 +134,17 @@ export class EnvironmentService {
     return this.configService.get<string>('MAIL_FROM_NAME', 'Docmost');
   }
 
+  getMailBlockedRecipientDomains(): string[] {
+    const raw = this.configService.get<string>(
+      'MAIL_BLOCKED_RECIPIENT_DOMAINS',
+      '',
+    );
+    return raw
+      .split(',')
+      .map((d) => d.trim().toLowerCase())
+      .filter(Boolean);
+  }
+
   getSmtpHost(): string {
     return this.configService.get<string>('SMTP_HOST');
   }
diff --git a/apps/server/src/integrations/mail/mail.service.ts b/apps/server/src/integrations/mail/mail.service.ts
index dd71cb559..22f6916f5 100644
--- a/apps/server/src/integrations/mail/mail.service.ts
+++ b/apps/server/src/integrations/mail/mail.service.ts
@@ -17,6 +17,10 @@ export class MailService {
   ) {}
 
   async sendEmail(message: MailMessage): Promise<void> {
+    if (this.isRecipientBlocked(message.to)) {
+      return;
+    }
+
     if (message.template) {
       // in case this method is used directly. we do not send the tsx template from queue
       message.html = await render(message.template, {
@@ -35,6 +39,10 @@ export class MailService {
   }
 
   async sendToQueue(message: MailMessage): Promise<void> {
+    if (this.isRecipientBlocked(message.to)) {
+      return;
+    }
+
     if (message.template) {
       // transform the React object because it gets lost when sent via the queue
       message.html = await render(message.template, {
@@ -47,4 +55,11 @@ export class MailService {
     }
     await this.emailQueue.add(QueueJob.SEND_EMAIL, message);
   }
+
+  private isRecipientBlocked(to: string): boolean {
+    const blocked = this.environmentService.getMailBlockedRecipientDomains();
+    if (blocked.length === 0) return false;
+    const domain = to?.split('@')[1]?.toLowerCase();
+    return !!domain && blocked.includes(domain);
+  }
 }