diff --git a/app/mailbox_utils.py b/app/mailbox_utils.py
index 47755223..ad37b718 100644
--- a/app/mailbox_utils.py
+++ b/app/mailbox_utils.py
@@ -22,6 +22,16 @@ class MailboxError(Exception):
         self.msg = msg
 
 
+class OnlyPaidError(MailboxError):
+    def __init__(self):
+        self.msg = "Only available for paid plans"
+
+
+class CannotVerifyError(MailboxError):
+    def __init__(self, msg: str):
+        self.msg = msg
+
+
 MAX_ACTIVATION_TRIES = 3
 
 
@@ -36,7 +46,7 @@ def create_mailbox(
         LOG.i(
             f"User {user} has tried to create mailbox with {email} but is not premium"
         )
-        raise MailboxError("Only premium plan can add additional mailbox")
+        raise OnlyPaidError()
     if not is_valid_email(email):
         LOG.i(
             f"User {user} has tried to create mailbox with {email} but is not valid email"
@@ -162,20 +172,20 @@ def verify_mailbox_code(user: User, mailbox_id: int, code: str) -> Mailbox:
     if activation.tries >= MAX_ACTIVATION_TRIES:
         LOG.i(f"User {user} failed to verify mailbox {mailbox_id} more than 3 times")
         clear_activation_codes_for_mailbox(mailbox)
-        raise MailboxError("Invalid activation code. Please request another code.")
+        raise CannotVerifyError("Invalid activation code. Please request another code.")
     if activation.created_at < arrow.now().shift(minutes=-15):
         LOG.i(
             f"User {user} failed to verify mailbox {mailbox_id} because code is too old"
         )
         clear_activation_codes_for_mailbox(mailbox)
-        raise MailboxError("Invalid activation code. Please request another code.")
+        raise CannotVerifyError("Invalid activation code. Please request another code.")
     if code != activation.code:
         LOG.i(
             f"User {user} failed to verify mailbox {mailbox_id} because code does not match"
         )
         activation.tries = activation.tries + 1
         Session.commit()
-        raise MailboxError("Invalid activation code")
+        raise CannotVerifyError("Invalid activation code")
     LOG.i(f"User {user} has verified mailbox {mailbox_id}")
     mailbox.verified = True
     clear_activation_codes_for_mailbox(mailbox)
diff --git a/tests/api/test_mailbox.py b/tests/api/test_mailbox.py
index 813eb3cd..085a42aa 100644
--- a/tests/api/test_mailbox.py
+++ b/tests/api/test_mailbox.py
@@ -42,7 +42,7 @@ def test_create_mailbox_fail_for_free_user(flask_client):
     )
 
     assert r.status_code == 400
-    assert r.json == {"error": "Only premium plan can add additional mailbox"}
+    assert r.json == {"error": "Only available for paid plans"}
 
 
 def test_delete_mailbox(flask_client):
diff --git a/tests/test_mailbox_utils.py b/tests/test_mailbox_utils.py
index 7e076955..1b37345d 100644
--- a/tests/test_mailbox_utils.py
+++ b/tests/test_mailbox_utils.py
@@ -30,7 +30,7 @@ def test_free_user_cannot_add_mailbox():
     user.lifetime = False
     email = random_email()
     try:
-        with pytest.raises(mailbox_utils.MailboxError):
+        with pytest.raises(mailbox_utils.OnlyPaidError):
             mailbox_utils.create_mailbox(user, email)
     finally:
         user.lifetime = True
@@ -214,7 +214,7 @@ def test_verify_fail():
         try:
             mailbox_utils.verify_mailbox_code(user, mailbox.id, "9999999")
             assert False, f"test {i}"
-        except mailbox_utils.MailboxError:
+        except mailbox_utils.CannotVerifyError:
             activation = MailboxActivation.get_by(mailbox_id=mailbox.id)
             assert activation.tries == i + 1
 
@@ -225,7 +225,7 @@ def test_verify_too_may():
     activation = MailboxActivation.get_by(mailbox_id=mailbox.id)
     activation.tries = mailbox_utils.MAX_ACTIVATION_TRIES
     Session.commit()
-    with pytest.raises(mailbox_utils.MailboxError):
+    with pytest.raises(mailbox_utils.CannotVerifyError):
         mailbox_utils.verify_mailbox_code(user, mailbox.id, activation.code)
 
 
@@ -235,7 +235,7 @@ def test_verify_too_old_code():
     activation = MailboxActivation.get_by(mailbox_id=mailbox.id)
     activation.created_at = arrow.now().shift(minutes=-30)
     Session.commit()
-    with pytest.raises(mailbox_utils.MailboxError):
+    with pytest.raises(mailbox_utils.CannotVerifyError):
         mailbox_utils.verify_mailbox_code(user, mailbox.id, activation.code)