Test 4 Communication error failure

Hello.

Thank you for this great plugin.
I’m encountering a failure issue with test case 4: Communication error. User a gets a “transaction did not succed”
All other tests have been passed.
However for test 4 bank refers failure.

The case relates to ResultCode=500

Could you guess what’s wrong and what’s the fix?

Thank you

https://ww.wp.xz.cn/plugins/woo-payment-gateway-piraeus-bank-greece/