diff --git a/src/calibre/gui2/wizard/send_email.py b/src/calibre/gui2/wizard/send_email.py
index 8f41280516..38c92e5782 100644
--- a/src/calibre/gui2/wizard/send_email.py
+++ b/src/calibre/gui2/wizard/send_email.py
@@ -67,12 +67,17 @@ class TestEmail(QDialog):
         t.start()
 
     def run_test(self):
-        try:
-            tb = self.test_func(str(self.to.text())) or _('Email successfully sent')
-        except Exception:
-            import traceback
-            tb = traceback.format_exc()
-        self.test_done.emit(tb)
+        from email.utils import parseaddr
+        addr = parseaddr(self.to.text().strip())[-1]
+        if not addr:
+            tb = f'{self.to.text().strip()} is not a valid email address'
+        else:
+            try:
+                tb = self.test_func(addr) or _('Email successfully sent')
+            except Exception:
+                import traceback
+                tb = traceback.format_exc()
+            self.test_done.emit(tb)
 
     def on_test_done(self, txt):
         if self.isVisible():