diff --git a/token-validator/challenge.go b/token-validator/challenge.go
index 9f18b99..fe8fc7f 100644
--- a/token-validator/challenge.go
+++ b/token-validator/challenge.go
@@ -14,6 +14,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/go-sql-driver/mysql"
 	"github.com/julienschmidt/httprouter"
 
 	"git.nemunai.re/srs/adlin/libadlin"
@@ -414,6 +415,9 @@ func receiveToken(r *http.Request, body []byte, chid int) (interface{}, error) {
 		}
 
 		if _, err := std.UnlockNewChallenge(chid, gt.Token); err != nil {
+			if me, ok := err.(*mysql.MySQLError); ok && me.Number == 1062 {
+				return "Already validated", nil
+			}
 			log.Println(err)
 			return nil, err
 		}