250 EM_MUSTUSETLS TLS connection is required.
A non-TLS encrypted connection attempt was made to a server that is configured to only accept TLS connections. The server responded on the legacy port (1025) with error parcel ErrGTWMustUseTLS(8059). This indicates that the server is listening on the legacy port, but is not accepting connections on that port, only on the TLS port.
Retry the connection to the server using a sslmode that uses TLS (i.e. prefer, require, verify-ca, or verify-full).