Significant issues synchronising an email account - is this a tls/ssl issue

I setup emClient for a home user whose email server is in New Zealand
It was a pig to setup because it would not synchronise correctly and I put it down to them

However the client has been in touch with them and suggested that her email client (emClient) is not using the most up to date settings. They have provided this link https://www.spark.co.nz/help/servicealert/emailservicealert

Are they right or wrong?

Anyone have any clues? I may have to remove emClient if I cannot resolve

Steve