Hi, @kissu. There is no application runtime for the deployed site (with the exceptions of Functions but you haven’t mentioned those). This is covered in the support guide listed above.
Did you read that support guide and try the solutions there? If so, what steps did you take and what were the results? Would you please send us a link to the site and explain what steps are required to see the error there?
Edit: change “node runtime” to “no application runtime”