I have tried with current files (October 22, 2017) and the same issue.

Should I wait the next release?

I will have to do some more testing.

I will keep you posted on any update (next release it should be fixed, but i could push a quick fix update once i fixed it in source).

I have updated to SolidCP 1.4. When I install (free) Lets Encrypt Certificate and get this message:

LetsEncrypt Certificate successfully installed on website

But the certificate is not installed.

In audit log:

Source:
xxxxx

Task Name:
ImportCertificate

Item Name:

User:
xxxxx

Started:
2/14/2018 1:18:56 AM

Finished:
2/14/2018 1:18:58 AM

Duration:
00:00:01

Severity:
Error

Execution Log:

System.InvalidOperationException: Sequence contains no matching element at System.Linq.Enumerable.First[TSource](IEnumerable`1 source, Func`2 predicate) at SolidCP.Providers.Web.Iis.SSLModuleService80.GetCurrentSiteCertificate(WebSite website) at SolidCP.Providers.Web.Iis.SSLModuleService80.ImportCertificate(WebSite website)

How disable Lets Encrypt Certificate on SolidCP 1.4?

Option has not been added yet.

We focussed on fixing the reported bugs in regard to LE instead with 1.4.0.