When attempting to create a Salesforce form within the CMS the the following error message may be thrown. This is may be caused by Salesforce disabling support for TLS1.0 as noted in the following excerpt. Support of TLS 1.2 was not supported for Salesforce until EPiServer.MarketingAutomationIntegration.Salesforce 188.8.131.5200.
Starting in June 2016, Salesforce will begin disabling the TLS 1.0 encryption protocol using a phased approach. This phased approach will prevent it from being used to access the Salesforce service within inbound and outbound connections.
At Salesforce, trust is our #1 value, and we take the protection of our customers' data very seriously. The disablement of TLS 1.0 is being undertaken so we can maintain the highest security standards and promote the safety of your data as well as align with industry-wide best practices.
After TLS 1.0 is disabled, any inbound connections to or outbound connections from your Salesforce org will need to use the TLS 1.1 or TLS 1.2 encryption protocol. This change also impacts access to websites, such as Salesforce Communities, Customer and Partner portals, Force.com sites, and Site.com. As a result, users of your Salesforce Communities, Customer and Partner portals, and your Salesforce hosted websites are also affected by this. Salesforce has already enabled TLS 1.1 and TLS 1.2 for outbound connections from Salesforce, and TLS 1.2 is already enabled in connections to Salesforce.
We recommend that you test this update in a sandbox or Developer Edition org to verify end-to-end compatibility before enabling it in your production org.
To add support for TLS 1.2 for the purposes of Salesfoce upgrade to at least EPiServer.MarketingAutomationIntegration.Salesforce 184.108.40.20600.