diff --git a/preauth_keys.go b/preauth_keys.go
index 05af926..de10cdb 100644
--- a/preauth_keys.go
+++ b/preauth_keys.go
@@ -11,7 +11,7 @@ import (
 
 const errorAuthKeyNotFound = Error("AuthKey not found")
 const errorAuthKeyExpired = Error("AuthKey expired")
-const errorAuthKeyNotReusableAlreadyUsed = Error("AuthKey not reusable already used")
+const errSingleUseAuthKeyHasBeenUsed = Error("AuthKey has already been used")
 
 // PreAuthKey describes a pre-authorization key usable in a particular namespace
 type PreAuthKey struct {
@@ -21,7 +21,7 @@ type PreAuthKey struct {
 	Namespace   Namespace
 	Reusable    bool
 	Ephemeral   bool `gorm:"default:false"`
-	Used bool `gorm:"default:false"`
+	Used        bool `gorm:"default:false"`
 
 	CreatedAt  *time.Time
 	Expiration *time.Time
@@ -112,7 +112,7 @@ func (h *Headscale) checkKeyValidity(k string) (*PreAuthKey, error) {
 	}
 
 	if len(machines) != 0 || pak.Used {
-		return nil, errorAuthKeyNotReusableAlreadyUsed
+		return nil, errSingleUseAuthKeyHasBeenUsed
 	}
 
 	return &pak, nil
diff --git a/preauth_keys_test.go b/preauth_keys_test.go
index 364733a..f8973ea 100644
--- a/preauth_keys_test.go
+++ b/preauth_keys_test.go
@@ -87,7 +87,7 @@ func (*Suite) TestAlreadyUsedKey(c *check.C) {
 	h.db.Save(&m)
 
 	p, err := h.checkKeyValidity(pak.Key)
-	c.Assert(err, check.Equals, errorAuthKeyNotReusableAlreadyUsed)
+	c.Assert(err, check.Equals, errSingleUseAuthKeyHasBeenUsed)
 	c.Assert(p, check.IsNil)
 }
 
@@ -191,5 +191,5 @@ func (*Suite) TestNotReusableMarkedAsUsed(c *check.C) {
 	h.db.Save(&pak)
 
 	_, err = h.checkKeyValidity(pak.Key)
-	c.Assert(err, check.Equals, errorAuthKeyNotReusableAlreadyUsed)
+	c.Assert(err, check.Equals, errSingleUseAuthKeyHasBeenUsed)
 }