pgAdmin4 - postgresql application server could not be contacted

When starting postgres, I get the following error:

postgresql application server could not be contacted.

When running as administrator the error is "solved", but the application opens in another port - sometimes it opens in 50142, 51120 and others in 50859 -. And when it opens on another port (like the ones previously said), it asks for the password to connect to the server and I get this error:

could not connect to server: Connection refused (0x0000274D/10061) Is the server running on host "localhost" (::1) and accepting TCP/IP connections on port 5432? could not connect to server: Connection refused (0x0000274D/10061) Is the server running on host "localhost" (127.0.0.1) and accepting TCP/IP connections on port 5432?

Info:

• Windows 10 64Bits
• Postgresql 10
• pgAdmin 4.1
• Port 5432 (appears even in PostgreSQL\10\data\postgres.conf)

Solutions already tried:

• Run in administrator mode
• Modify the postgres.conf file
• Clear the contents of the folder AppData\Roaming\pgAdmin

I would like to know how to avoid this error when starting the application and always opening on a specific port.

Simply locate AppData\Roaming\pgAdmin, delete the pgAdmin folder and try to start pgAdmin again... It should work