CODEWITHSUNDEEP
c#twiliosendmessage
Luke Rohde
Luke Rohde

Reputation: 261

Twilio C# SendMessage suddenly returning null

We've been using the twilio C# client for asp.net MVC for a long time without trouble. It recently stopped working, with SendMessage returning null. Investigation suggests some kind of SSL issue. https://github.com/twilio/twilio-csharp/issues/126

I suspect this has something to do with dropping support for SSLv3. https://www.twilio.com/blog/2014/10/security-notification-for-sslv3-poodle-vulnerability.html

Unfortunately we ring-fenced our Microsoft development years ago (all new development is linux/rails) so we're stuck using a bunch of old windows crap. I'm stuck on VS2005 and had to build the twilio c# client myself. Rebuilding the DLLs from the latest github source hasn't helped.

I can send SMS my old windows xp development machine with .net 3.5, but not in production on windows 2003R2.

This didn't help

System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls;

and don't have TLS 1.2 in .net 3.5 so can't do this

System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

What can we do?

Upvotes: 2

Views: 924

Answers (1)

philnash
philnash

Reputation: 73055

Twilio developer evangelist here.

This is an SSL/TLS issue in that we recently upgraded the SSL certificate for api.twilio.com to a SHA2-signed certificate.

To mitigate this change right now, you can update your application to use api.twilio.com:8443 which is maintaining the old certificate. However that will only be available until the end of this year (31 December 2015).

To fix it overall, you will likely need to update your SSL libraries. I'm afraid I do not know how to do that on the Windows servers you mention.

Please see this post for more details and ways to test.

Upvotes: 2

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