diff --git a/ui-ngx/src/app/modules/home/pages/admin/mail-server.component.html b/ui-ngx/src/app/modules/home/pages/admin/mail-server.component.html
index 2762e0d43a..926ad64644 100644
--- a/ui-ngx/src/app/modules/home/pages/admin/mail-server.component.html
+++ b/ui-ngx/src/app/modules/home/pages/admin/mail-server.component.html
@@ -331,7 +331,7 @@
           </fieldset>
           <div fxLayout="row" fxLayoutAlign="end center" fxLayout.xs="column" fxLayoutAlign.xs="end" fxLayoutGap="16px">
             <button mat-raised-button type="button"
-                    [disabled]="(isLoading$ | async) || mailSettings.invalid || domainForm.invalid || (mailSettings.dirty || domainForm.dirty)"
+                    [disabled]="(isLoading$ | async) || mailSettings.get('enableOauth2').value ? mailSettings.invalid || domainForm.invalid || (mailSettings.dirty || domainForm.dirty) : mailSettings.invalid"
                     (click)="sendTestMail()">
               {{'admin.send-test-mail' | translate}}
             </button>
diff --git a/ui-ngx/src/app/modules/home/pages/admin/mail-server.component.ts b/ui-ngx/src/app/modules/home/pages/admin/mail-server.component.ts
index 6815c81e31..d95c3d6096 100644
--- a/ui-ngx/src/app/modules/home/pages/admin/mail-server.component.ts
+++ b/ui-ngx/src/app/modules/home/pages/admin/mail-server.component.ts
@@ -416,6 +416,9 @@ export class MailServerComponent extends PageComponent implements OnInit, OnDest
   private get mailSettingsFormValue(): MailServerSettings {
     const formValue = this.mailSettings.getRawValue() as Required<typeof this.mailSettings.value>;
     delete formValue.changePassword;
+    if (!isDefinedAndNotNull(formValue.password)) {
+      delete formValue.password;
+    }
     return formValue;
   }