SSL issues

Hi,

My context:

• a SharePoint Server 2013 on Premise farm with 3 webApps in https mode
  • https://intranet.mydomain.com
  • https://perso.mydomain.com
  • https://admin.mydomain.com
• a wildcard SSL certificate from GeoTrust (*.mydomain.com)
• this certificate is applied to the 3 IIS SharePoint sites

My issue:

All day long, without any detectable reasons from logs reading, the SSL certificate is deselected. In the "bindings" section in IIS manager, the drop down list is set to "Net Selected"... When this append, obviously sites are unreachable.

My leads:

• in CA : Security > General Security > Manage Trust. I added the SSL wildcard certificate and the root CA from GeoTrust
• I switch the SSL wildcard certificate from GeoTrust by a certificate issued from the organization CA. Nothing changed :/

Does anyone have ideas !!

Thanks