Dear @Dhanvir_sing_rawat
According to our inspection, the grievance portal of the Ghaziabad Nagar Nigam is currently down due to server outage or there is some technical error.
Meanwhile, you can use the Jansunwai portal of the Uttar Pradesh government (mentioned in the post) to raise your complaint with the Municipal Corporation by selecting the Department of Urban Development & Local Bodies then the Nagar Nigam. You can also use e-NagarSewa UP portal.