Issue connecting to cPanel Linux Caldav server

Hello,

I am using EM Client since about two months now.  It is a great way to bring together calendar from various providers : gMail, exchange, Caldav, …

Since about mid last week, it seems the connectivity to my CalDav server is lost.

I have tested connectivity from a Mac, it works fine.  iOS & MacOS are only officially supported platform for cPanel :
 “We have only tested these steps on Apple®-distributed products. These clients natively support CalDAV and CardDAV. If you use other calendar or contacts applications that support these protocols, you  may  be able to access your calendars and contacts from those applications.”

 https://documentation.cpanel.net/display/CKB/How+to+Set+Up+Calendars+and+Contacts)

Does EM Client use a slightly different implementation than MacOS / iOS, which creates compatibility issues under some circumstances ?  That would be unfortunate for me as I will need to find another solution.

With kind regards, Michel

p.s. : the logs are as following : 
14:25:28 CreaXum [CalDAV / CardDAV]  MailClient.Accounts.ConnectionException: The server committed a protocol violation. Section=ResponseStatusLine —> System.Net.WebException: The server committed a protocol violation. Section=ResponseStatusLine
14:25:28    at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
14:25:28    at MailClient.Protocols.CalDav.ProtocolCommands.RequestCommand.Execute(HttpWebRequest httpRequest, CancellationToken cancellationToken, Action1 logBody) 14:25:28    at MailClient.Protocols.CalDav.ProtocolCommands.XmlRequestCommand.Execute(HttpWebRequest httpRequest, CancellationToken cancellationToken, Action1 logBody)
14:25:28    at MailClient.Protocols.CalDav.ProtocolCommands.Connector.RunCommand(CalDavAccount account, ICommand command, CancellationToken cancellationToken)
14:25:28    — End of inner exception stack trace —
14:25:28    at MailClient.Protocols.CalDav.ProtocolCommands.Connector.RunCommand(CalDavAccount account, ICommand command, CancellationToken cancellationToken)
14:25:28    at MailClient.Protocols.CalDav.Synchronizer.BootstrapCommand.UpdatePrincipalUri(Uri baseUri)
14:25:28    at MailClient.Protocols.CalDav.Synchronizer.BootstrapCommand.Execute(WorkerStatus status)
14:25:28    at MailClient.Commands.Command.Process(WorkerStatus status)

Update : after dwelling these forums a bit longer, I located one user that successfully connected using EM Client V7.1.33506.0 to CPanel Caldav.

I have also been successful with this version of the software. It seems this issue is a regression introduced with V 7.2x