W3 total cache

Hi sir,
Please,
Hi sir,
I added ex: fhg36h_t3yvf3g3
Under “Cache Exception List”

But it is not working. I am still see the message at I must enter login in the field ache Exception List.

So please, How can i fix this error ?

Thanks
A.J.

https://wordpress.org/plugins/rename-wp-login/