diff --git a/server/handler.go b/server/handler.go
index 184991a..82c9536 100644
--- a/server/handler.go
+++ b/server/handler.go
@@ -54,13 +54,14 @@ func AdvertiseHandler(store peering.Store, key *rsa.PublicKey, funcs ...OptionFu
 			return
 		}
 
-		if _, err := store.Get(serverClaims.PeerID); err == nil {
+		_, err = store.Get(serverClaims.PeerID)
+		if err == nil {
 			logger.Printf("[WARN] %s", errors.WithStack(ErrPeerIDAlreadyInUse))
 			options.ErrorHandler(w, r, ErrPeerIDAlreadyInUse)
 			return
 		}
 
-		if err != peering.ErrPeerNotFound {
+		if !errors.Is(err, peering.ErrPeerNotFound) {
 			logger.Printf("[ERROR] %+v", errors.WithStack(err))
 			options.ErrorHandler(w, r, err)
 			return