WP_FAIL2BAN_BLOCKED_USERS already defined

I am receiving the message: PHP Warning: Constant WP_FAIL2BAN_BLOCK_USER_ENUMERATION already defined in wp-config.php
I have the FAIL"BAN_Proxies defined one line underneath that and I don’t get an error for THAT definition.

I checked to make sure the definitions are above the line that says:
/* That's all, stop editing! Happy publishing. */

What other reasons might cause that issue?

Kind regards,
Martin

Sorry, this rather fell off the bottom of the list.

Did you work out what the problem was?