diff --git a/packages/teams-js/src/internal/emailAddressValidation.ts b/packages/teams-js/src/internal/emailAddressValidation.ts
index ba25b61cf7..a361826e5d 100644
--- a/packages/teams-js/src/internal/emailAddressValidation.ts
+++ b/packages/teams-js/src/internal/emailAddressValidation.ts
@@ -1,6 +1,9 @@
-export function validateEmailAddress(emailString: string): void {
-  const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
-  if (!emailRegex.test(emailString)) {
+export function validateEmailAddress(emailString: string | null | undefined): void {
+  const emailIsEmptyOrUndefined = emailString ? emailString.length <= 0 : true;
+  const atIndex = emailString?.indexOf('@');
+  const periodIndexAfterAt = emailString?.indexOf('.', atIndex);
+
+  if (emailIsEmptyOrUndefined || atIndex === -1 || periodIndexAfterAt === -1) {
     throw new Error('Input email address does not have the correct format.');
   }
 }
diff --git a/packages/teams-js/test/internal/emailAddressValidation.spec.ts b/packages/teams-js/test/internal/emailAddressValidation.spec.ts
index 49d39b3348..1721c9a201 100644
--- a/packages/teams-js/test/internal/emailAddressValidation.spec.ts
+++ b/packages/teams-js/test/internal/emailAddressValidation.spec.ts
@@ -1,7 +1,7 @@
 import { validateEmailAddress } from '../../src/internal/emailAddressValidation';
 
 describe('emailAddressValidation', () => {
-  const invalidEmails = ['@@domain.com', 'firstname lastname@domain.com', 'name@domain'];
+  const invalidEmails = ['domain.com', 'name.domain@com', 'name@domain', '', null];
   invalidEmails.forEach((invalidEmail) => {
     it('should throw errors for invalid email addresses', () => {
       expect(() => validateEmailAddress(invalidEmail)).toThrow('Input email address does not have the correct format.');
@@ -16,8 +16,9 @@ describe('emailAddressValidation', () => {
   validEmails.forEach((validEmail) => {
     it('should not throw errors for valid email addresses', () => {
       expect(() => validateEmailAddress(validEmail)).not.toThrow(
-        'Input email address does not have the correct format.',
+        'Input email address does not have the correct format.'
       );
     });
   });
 });
+
diff --git a/packages/teams-js/test/public/emailAddress.spec.ts b/packages/teams-js/test/public/emailAddress.spec.ts
index 3dae0726e1..4545ed18d8 100644
--- a/packages/teams-js/test/public/emailAddress.spec.ts
+++ b/packages/teams-js/test/public/emailAddress.spec.ts
@@ -1,7 +1,7 @@
 import { EmailAddress } from '../../src/public';
 
 describe('emailAddress', () => {
-  const invalidEmails = ['@@domain.com', 'firstname lastname@domain.com', 'name@domain'];
+  const invalidEmails = ['domain.com', 'name.domain@com', 'name@domain'];
   invalidEmails.forEach((invalidEmail) => {
     it('should throw errors for invalid email addresses', () => {
       expect(() => new EmailAddress(invalidEmail)).toThrowError(