cant translate a label

Hi! I am loving the plugin, it is very helpfull.

I just have a tiny problem.

I was able to translate the plugin via loco translate and also with the “Labels Edit” section of this plugin.
Except one line that just wont appear in any of those options:

Error: The username and password combination is wrong.

Can you help me with this?
Thanks in advance

The page I need help with: [log in to see the link]