Blockchain API test returns error

[thonglor]

Hi all,

I'm trying to implement and use the Blockchain API(s). On their website https://blockchain.info/api/api_receive when I enter a Receiving Address and a Callback URL and then "Fire Test Callback" there always comes the red error mesage "Error Input String May Contain HTML". Why is that or what am I doing wrong? 

Thanks for help!

[williamj2543]

Getting that also