Blocked IP from Whitelist

`Hi,
One of our branches started to be blocked by wordfence.
He gets the 503 message.
At the first time I could see that this IP in shown in the wordfence logs.
I added the IP to the Wordfence Whitelist and all worked OK.
Yesterday, same IP was blocked again.
Now I cannot see it’s logs on Wordfence.
I check the white list and same IP shown there.
Checked with the hosting company and they claim no block for this IP on their side.
Checked on the internet for blocked IP and some sites claim it is not blocked and some shows it is blocked in dnsbl.sorbs.net, dnsbl.spfbl.net and dnsbl-3.uceprotect.net.
This IP is our branch. How can I make sure they could logged into our site?
* I also set off Brute force and Rate limit.