Android ADB on WiFi: unable to connect to

For any reason, adb (via Wifi) cannot connect to device with error:

unable to connect to <ip address>:<port>

Try to restarts the adbd (on device) daemon listening on TCP on the specified port, by running adb command tcpip, with USB connected to device.

$ ./adb tcpip 5555

then connect again.

$ ./adb connect 192.168.1.111

Related:
- Setup Android adb for Wifi debug