Why doesn't sync2em sync properly to iphone?

I recently downloaded eM Client because i was convinced it would supply me with a better solution for synching my calendar properly with iphone. I created a free temporary trial lisence for sync2em, followed the directions on the site and inserted sync2em as a new microsoft exchange account in my iphone.

Expecting to be satisfied, i opened my iphone calendar and discovered it was empty, although the “exchange calendar”, which is the one supposed to be synced with eM Client, was checked.

Why doesn’t it sync? Have I done something wrong?

Thanks a lot

So I think i figured out what the problem is. There’s an error saying that the connection to sync2em was failed everytime I open em client:
“[CalDAV / CardDAV] An attempt to connect to [email protected] failed. This could be caused by temporary server unavailability or incorrect settings. Do you want to check the settings?”

I can’t find anything wrong with the settings and my internet works just fine.
i would be entirely grateful if anyone could lighten my eyes about this issue.