Version Note: This answer applies to EXM 3.5 or Sitecore 9.X only.
You can configure EXM.RendererUrl
in the Sitecore.EmailExperience.Core.config
config file.
In case the setting is empty, the RendererUrl
is resolved on the first request to the application. In the <httpRequestBegin>
pipeline, there is a Sitecore.Modules.EmailCampaign.Core.Pipelines.HttpRequestBegin.OnHttpRequestBegin
processor that that does that:
GlobalSettings.RendererUrl = WebUtil.GetServerUrl(args.HttpContext.Request.Url, false);
You said that it worked ok previously on HTTP, but after you switched to HTTPS, it does not work. First I would focus on fixing the SSL/TLS issue. I bet that there is some problem with the certificate.