SSL connection error with iOs11

[relaxmax]

Nextcloud version : 13.0.6
Operating system and version : Iphone6 ioS11
PHP version : 7.0.30

My friend have bought a new Iphone 6 and he has his own account on my nextcloud server.

Our Nextcloud works well with windows, Androïd, Linux… but impossible to configure a Caldav or Carddav access with IPhone 6 Ios11 : per exemble, i create a new account with Caldav, enter the correct informations and then i have the message: «Impossible te connect with SSL. Would you try to connect without SSL ?»

Answer No gives the same error.
Answer Yes is OK but they’re is no synchronization.

Please help or we must return to Google Thanks !

[rakekniven]

Check server log (webserver and nextcloud) to see what happens when app is connecting.

[relaxmax]

Thanks a lot for your answer !
I checked the logs : nextcloud.log, access.log, error.log but nothings appears except connection ssl timed out…
I read several wikis about SSL and i learnt that SSL is working with datetime. So i set the date.timezone (who was commented) in the php.ini of my server and now it works !