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Suddenly receiving Connection Failure


Suddenly receiving Connection Failure

Hello -


I've been using the same code and integration for well over a year and today I started getting Connection Failures every time I call the APIs ("")...I believe around 11am this morning.  Is it possible anything changed or I may have inadvertently changed something?  


Thanks - Steve

Occasional Participant

Re: Suddenly receiving Connection Failure

I started having the same problem this morning, I'm using the C# library and got this error "ConstantContactUtility.ConstantException: The underlying connection was closed: An unexpected error occurred on a send. ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a send. ---> System.IO.IOException: Authentication failed because the remote party has closed the transport stream."


I hope someone can help us :(


Re: Suddenly receiving Connection Failure

I'm using some custom Coldfusion classes I designed (so long ago I barely remembered where all the files were), I haven't had a single API class fail since I put the code in place (and I add about 50 new contacts a day).  I wonder if their API endpoint is trying to force a specific version of TLS or something (on the version of Coldfusion I use the http function doesn't support TLS 1.2...but this kind of change is typically communicated long in advance).  I do have a way around this but I don't want to start changing code that's been in place in prod for this long unless I need to.  


The exact string I'm getting back is "Connection Failure. Status code unavailable."


Re: Suddenly receiving Connection Failure

Hello @imru and @JuanG126,


Thank you for reaching out to Constant Contact's API Support.


Your assessment of TLS 1.2 is correct. Back on August 23rd 2018 we made a forum post as well as a techblog post, and we emailed the main email address attached to the API Key in Mashery accounts that our provider of API Keys (Mashery) would no longer be supporting TLS 1.0/1.1. Here is the link to that forum post.


The announcement was in August. The official support of TLS 1.0/1.1 has stopped in September and as of 3/5/19 at around 10am Eastern Mashery began to block any connection that was not TLS 1.2.

Jimmy D.
Tier II API Support Engineer
Occasional Participant

Re: Suddenly receiving Connection Failure

Thank you @imru and @Jimmy_D, I got it working now :)


Have a nice day!