Hi Seckin,
I have tried to replicate the issue on our end but the added rates are working fine on the shop page when checked.
Which currency pair do you have that are not updating? Can you please let us know that the rates are not working for any server set in the ‘Exchange Rates’ link.
Also if you wish you can share an admin credentials of your site (WP and preferably FTP) at support at tychesoftwares dot freshdesk dot com, so we could login and check the mentioned issue.