Update Error-Message i can’t understand

Hi, please read the SUSPICIOUS ERROR message below when updating some (NOT ALL) plugins from Affiliates:

An error occurred while updating Affiliates Pro: Before you can receive product updates, you must first authenticate your subscription to Elegant Themes. To do this, you need to enter both your Elegant Themes username and your Elegant Themes API key in the Updates tab of your Themes and Plugins settings. To locate your API key, log in to your Elegant Themes account and navigate to the Account> API Key page. Find out more here. If you continue to receive this message, please verify that your username and API key have been entered correctly.

I am authenticated with elegant themes API key every time! Why comes this message by updating affiliates pro? The same message comes by updating the Affiliates WooCommerce Integration.

Only the Affiliates Contact Form 7 Integration AND Affiliates by Username Update works fine every time

Hope you can help me?

Thanks

Gregor