"Can not validate return address" Shapeshift

[abit]

Use account name only. The public key won't work.
Wait or push them.

[bitcoinba]

Hello,

I am trying to send BTS to Shapeshift but I am getting the following error: "Can not validate return address". I have tried inputing my account name and the public key, I get the same error. Unfortunately, Shapeshift has not replied since yesterday.

Does anyone have any insight to the issue?

Thanks