diff --git a/cmd/bucket-replication.go b/cmd/bucket-replication.go
index e4bf92414..69519659a 100644
--- a/cmd/bucket-replication.go
+++ b/cmd/bucket-replication.go
@@ -730,9 +730,12 @@ func putReplicationOpts(ctx context.Context, sc string, objInfo ObjectInfo) (put
 		putOpts.Mode = rmode
 	}
 	if retainDateStr, ok := lkMap.Lookup(xhttp.AmzObjectLockRetainUntilDate); ok {
-		rdate, err := time.Parse(time.RFC3339, retainDateStr)
+		rdate, err := time.Parse(iso8601TimeFormat, retainDateStr)
 		if err != nil {
-			return putOpts, err
+			rdate, err = time.Parse(time.RFC3339, retainDateStr)
+			if err != nil {
+				return putOpts, err
+			}
 		}
 		putOpts.RetainUntilDate = rdate
 		// set retention timestamp in opts
diff --git a/cmd/object-handlers.go b/cmd/object-handlers.go
index 2dfb7b9f3..1c9993c36 100644
--- a/cmd/object-handlers.go
+++ b/cmd/object-handlers.go
@@ -2998,7 +2998,7 @@ func (api objectAPIHandlers) PutObjectRetentionHandler(w http.ResponseWriter, r
 			}
 			if objRetention.Mode.Valid() {
 				oi.UserDefined[strings.ToLower(xhttp.AmzObjectLockMode)] = string(objRetention.Mode)
-				oi.UserDefined[strings.ToLower(xhttp.AmzObjectLockRetainUntilDate)] = objRetention.RetainUntilDate.UTC().Format(time.RFC3339)
+				oi.UserDefined[strings.ToLower(xhttp.AmzObjectLockRetainUntilDate)] = objRetention.RetainUntilDate.UTC().Format(iso8601TimeFormat)
 			} else {
 				oi.UserDefined[strings.ToLower(xhttp.AmzObjectLockMode)] = ""
 				oi.UserDefined[strings.ToLower(xhttp.AmzObjectLockRetainUntilDate)] = ""