diff --git a/apps/readest.koplugin/main.lua b/apps/readest.koplugin/main.lua
index 2ce54488..1b8a8a58 100644
--- a/apps/readest.koplugin/main.lua
+++ b/apps/readest.koplugin/main.lua
@@ -122,7 +122,7 @@ end
 
 function ReadestSync:tryRefreshToken()
     if self.settings.refresh_token and self.settings.expires_at
-        and self.settings.expires_at < os.time() - self.settings.expires_in / 2 then
+        and self.settings.expires_at < os.time() + self.settings.expires_in / 2 then
         local client = self:getSupabaseAuthClient()
         client:refresh_token(self.settings.refresh_token, function(success, response)
             if success then