Unable to connect to DB

Yes, at home. The ESP connects via WiFi and the Pi via Ethernet.

Have you used the same mysql server IP in the controllers as in node-red?

Yes.

This' what I see in the console:

Start Node-RED
 
Once Node-RED has started, point a browser at http://192.168.0.220:1880
On Pi Node-RED works better with the Firefox or Chrome browser
 
Use   node-red-stop                          to stop Node-RED
Use   node-red-start                         to start Node-RED again
Use   node-red-log                           to view the recent log output
Use   sudo systemctl enable nodered.service  to autostart Node-RED at every boot
Use   sudo systemctl disable nodered.service to disable autostart on boot
 
To find more nodes and example flows - go to http://flows.nodered.org
 
Starting as a systemd service.
17 Oct 22:26:44 - [error] [mysql:mysql] Database not connected
17 Oct 22:26:46 - [error] [mysql:mysql] Database not connected

@Colin I was able to reproduce the problem with a different app from my PC. So, the issue is ISP server related.

Thanks for helping.