TLS connection to Mosquitto MQTT broker not working

[kisa72]

Hi,

I'm trying to get TLS connectivity between my Windows PC runnning mqtt-spy and my Debian server running the Mosquitto broker.
They both connect fine with no security and with user/password security. So the main operation and connectivity is fine.
Then I try to connect using the TLS setup I mention below, MQTT-SPY just times out and fails to connect.

Through terminals on the same MQTT server I can successfully communicate using the certs using the mosquitto_sub and mosquitto_pub commands:-

Terminal1 - mosquitto_sub -h 192,168.0.206 -p 8883 -t test --cafile /home/certs/ca.crt --tls-version tlsv1.2
Terminal2 - mosquitto_pub -h 127.0.0.1 -t test -m "Hello"

When using MQTT-SPY for TLS, I use the following setup:-
I go into the Security tab and TLS tab,
TLS/SSL mode: CA certificate,
Protocol: TLSv1.2,
CA certificate file: C:\User\me\Downloads\CERTS\ca.crt

The ca.crt is the same one being used in the mosquitto_sub command above, but copied over to Windows via FTP (FileZilla).

I'm assuming I'm doing something wrong and that's it's probably minor due to a lack of understanding around TLS security.

Any help would be great thank you.