Monday, 25 June 2018

Resolve Error "Unable to Login to Dynamics CRM" after v9 update

Recently we have updated our Dynamics 365 to v9 and we are updating our applications to the latest version of SDK.

As per Microsoft Guideline, approach is to update apps to .NET Framework 4.6.2 and update CRM SDK to latest v9.0 assemblies. But application was still throwing same error message ("Unable to Login to Dynamics CRM").

One of my colleague pointed to a David Branscome's Post about moving away from TLS 1.0 and 1.1 to 1.2 and it reminded me about the post I read few days back.

Because our .NET assemblies were already updated so version 4.6.2 and it should be handling the TLS Protocol issue itself. But our application was still throwing the same error so we decided to try invoke TLS1.2 manually in our application before CrmServiceClient is instantiated. Following line was added to the code:

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

But it was still throwing same error and then we started looking at assembly references and app.config. In config we found that targetFramework was pointing to 4.5.2 and it worked when we changed to 4.6.2 (as shown below). Once it is updated connection will was created without any issue.

<httpRuntime targetFramework="4.6.2" />

Premjit Singh
Attendite Ltd.


  1. This post is much helpful for us. This is really very massive value to all the readers and it will be the only reason for the post to get popular with great authority.
    Microsoft Dynamics AX Online Training

  2. Very interesting,good job and thanks for sharing such a good blog.your article is so convincing that I never stop myself to say something about it.You’re doing a great job.Keep it up, For Microsoft Dynamics 365 services contact Dynamics Square.

  3. This is really a very good blog and thanks for sharing it with the community!Keep Posting Many Blogs Like this.
    crm software development company in chennai