Postgres SSL error

I'm trying to run a Drupal migration via SSH and drush (a command line shell), copying data from a postgres database to mysql.

It works fine for a while (~5 mins or so), but then I get the error:

SQLSTATE[HY000]: General error: 7 SSL [error] SYSCALL error: EOF detected

The postgres database connection seems to have gone, and I just get errors:

SQLSTATE[HY000]: General error: 7 no [error] connection to the server

It works fine locally, so I think the problem must be with postgres and running a script over SSH - but googling these errors returns nothing useful. Does anyone know what could be causing this?

Why is Postgres connection refused?

“Could not connect to server: Connection refused” To be sure that PostgreSQL is running, you can also restart it with systemctl restart postgresql. If this does not fix the problem, the most likely cause of this error is that PostgreSQL is not configured to allow TCP/IP connections.

Could be a timeout. first inspect the log (maybe change ssl_renegotiation_limit)

BTW: IIRC, the renegotiation does not take place after a fixed amount of time, but after a certain amount of transmitted characters (2GB?)