diff --git a/backend/src/emails/sendEmailTranslated.test.ts b/backend/src/emails/sendEmailTranslated.test.ts
index f35815d07..a3eb26314 100644
--- a/backend/src/emails/sendEmailTranslated.test.ts
+++ b/backend/src/emails/sendEmailTranslated.test.ts
@@ -78,26 +78,24 @@ describe('sendEmailTranslated', () => {
       })
     })
 
-    it('has "sendEmailTranslated" with result not(!) "null"', () => {
-      expect(result).toBeTruthy()
-    })
-
-    it('has "sendEmailTranslated" with result', () => {
-      expect(result).toMatchObject({
-        envelope: {
-          from: 'info@gradido.net',
-          to: ['stage1@gradido.net', 'support@gradido.net'],
-        },
-        message: expect.any(String),
-        originalMessage: expect.objectContaining({
-          to: 'stage1@gradido.net',
-          cc: 'support@gradido.net',
-          from: 'Gradido (nicht antworten) <info@gradido.net>',
-          attachments: [],
-          subject: 'Gradido: Try To Register Again With Your Email',
-          html: expect.stringContaining('Gradido: Try To Register Again With Your Email'),
-          text: expect.stringContaining('GRADIDO: TRY TO REGISTER AGAIN WITH YOUR EMAIL'),
-        }),
+    describe('call of "sendEmailTranslated"', () => {
+      it('has result', () => {
+        expect(result).toMatchObject({
+          envelope: {
+            from: 'info@gradido.net',
+            to: ['stage1@gradido.net', 'support@gradido.net'],
+          },
+          message: expect.any(String),
+          originalMessage: expect.objectContaining({
+            to: 'stage1@gradido.net',
+            cc: 'support@gradido.net',
+            from: 'Gradido (nicht antworten) <info@gradido.net>',
+            attachments: [],
+            subject: 'Gradido: Try To Register Again With Your Email',
+            html: expect.stringContaining('Gradido: Try To Register Again With Your Email'),
+            text: expect.stringContaining('GRADIDO: TRY TO REGISTER AGAIN WITH YOUR EMAIL'),
+          }),
+        })
       })
     })
 
diff --git a/backend/src/emails/sendEmailTranslated.ts b/backend/src/emails/sendEmailTranslated.ts
index 77c668493..3fe4177f4 100644
--- a/backend/src/emails/sendEmailTranslated.ts
+++ b/backend/src/emails/sendEmailTranslated.ts
@@ -32,7 +32,8 @@ export const sendEmailTranslated = async (params: {
     logger.info(`Emails are disabled via config...`)
     return null
   }
-  if (CONFIG.EMAIL_TEST_MODUS) {
+  // because 'CONFIG.EMAIL_TEST_MODUS' can be boolean 'true' or string '`false`'
+  if (CONFIG.EMAIL_TEST_MODUS === true) {
     logger.info(
       `Testmodus=ON: change receiver from ${params.receiver.to} to ${CONFIG.EMAIL_TEST_RECEIVER}`,
     )
diff --git a/backend/src/emails/sendEmailVariants.test.ts b/backend/src/emails/sendEmailVariants.test.ts
new file mode 100644
index 000000000..4ac8221a7
--- /dev/null
+++ b/backend/src/emails/sendEmailVariants.test.ts
@@ -0,0 +1,88 @@
+import CONFIG from '@/config'
+import { sendAccountMultiRegistrationEmail } from './sendEmailVariants'
+import { sendEmailTranslated } from './sendEmailTranslated'
+
+CONFIG.EMAIL = true
+CONFIG.EMAIL_SMTP_URL = 'EMAIL_SMTP_URL'
+CONFIG.EMAIL_SMTP_PORT = '1234'
+CONFIG.EMAIL_USERNAME = 'user'
+CONFIG.EMAIL_PASSWORD = 'pwd'
+
+jest.mock('./sendEmailTranslated', () => {
+  const originalModule = jest.requireActual('./sendEmailTranslated')
+  return {
+    __esModule: true,
+    sendEmailTranslated: jest.fn((a) => originalModule.sendEmailTranslated(a)),
+  }
+})
+
+describe('sendEmailVariants', () => {
+  let result: Record<string, unknown> | null
+
+  describe('sendAccountMultiRegistrationEmail', () => {
+    beforeAll(async () => {
+      result = await sendAccountMultiRegistrationEmail({
+        firstName: 'Peter',
+        lastName: 'Lustig',
+        email: 'peter@lustig.de',
+        language: 'en',
+      })
+    })
+
+    describe('calls "sendEmailTranslated"', () => {
+      it('with expected parameters', () => {
+        expect(sendEmailTranslated).toBeCalledWith({
+          receiver: {
+            to: 'Peter Lustig <peter@lustig.de>',
+          },
+          template: 'accountMultiRegistration',
+          locals: {
+            firstName: 'Peter',
+            lastName: 'Lustig',
+            locale: 'en',
+            resendLink: CONFIG.EMAIL_LINK_FORGOTPASSWORD,
+          },
+        })
+      })
+
+      it('has expected result', () => {
+        expect(result).toMatchObject({
+          envelope: {
+            from: 'info@gradido.net',
+            to: ['peter@lustig.de'],
+          },
+          message: expect.any(String),
+          originalMessage: expect.objectContaining({
+            to: 'Peter Lustig <peter@lustig.de>',
+            from: 'Gradido (nicht antworten) <info@gradido.net>',
+            attachments: [],
+            subject: 'Gradido: Try To Register Again With Your Email',
+            html:
+              expect.stringContaining(
+                '<title>Gradido: Try To Register Again With Your Email</title>',
+              ) &&
+              expect.stringContaining('>Gradido: Try To Register Again With Your Email</h1>') &&
+              expect.stringContaining(
+                'Your email address has just been used again to register an account with Gradido.',
+              ) &&
+              expect.stringContaining(
+                'However, an account already exists for your email address.',
+              ) &&
+              expect.stringContaining(
+                'Please click on the following link if you have forgotten your password:',
+              ) &&
+              expect.stringContaining(
+                `<a href="${CONFIG.EMAIL_LINK_FORGOTPASSWORD}">${CONFIG.EMAIL_LINK_FORGOTPASSWORD}</a>`,
+              ) &&
+              expect.stringContaining('or copy the link above into your browser window.') &&
+              expect.stringContaining(
+                'If you are not the one who tried to register again, please contact our support:',
+              ) &&
+              expect.stringContaining('Sincerely yours,<br><span>your Gradido team'),
+            text: expect.stringContaining('GRADIDO: TRY TO REGISTER AGAIN WITH YOUR EMAIL'),
+          }),
+        })
+      })
+    })
+  })
+})
diff --git a/backend/src/emails/sendEmailVariants.ts b/backend/src/emails/sendEmailVariants.ts
index e9823c5bf..fb142f206 100644
--- a/backend/src/emails/sendEmailVariants.ts
+++ b/backend/src/emails/sendEmailVariants.ts
@@ -1,12 +1,12 @@
-import { sendEmailTranslated } from './sendEmailTranslated'
 import CONFIG from '@/config'
+import { sendEmailTranslated } from './sendEmailTranslated'
 
 export const sendAccountMultiRegistrationEmail = (data: {
   firstName: string
   lastName: string
   email: string
   language: string
-}): Promise<boolean> => {
+}): Promise<Record<string, unknown> | null> => {
   return sendEmailTranslated({
     receiver: { to: `${data.firstName} ${data.lastName} <${data.email}>` },
     template: 'accountMultiRegistration',