I have a Cloud SQL Server on GCP, the CloudSQL part for e.g. of the N1 network

Here’s what I have done so far:

• Created a PSC (Private Service Connect) endpoint on the N1 subnet.
• I added a firewall rule for IP ranges with TCP port, allowing On-premise servers
  (N2 network) to access the PSC endpoint IP.
• The firewall rule has been successfully implemented.

However, the traffic is still not able to reach GCP. Via telnet

What additional steps or configurations might we be missing to ensure that traffic from our On-premise servers (N2 network)
can reach the Cloud SQL Server on GCP via the PSC endpoint in the N1 network?