Seems like you have installed security plugin on your wordpress admin page to make it accessable only through limited ip address.
You can disable your plugin via database by going into wp-config.php table than edit out active_plugins column and remove out your plugin array or disable it by replacing 1 with 0 (1= True/ Enable & 0 = False)
Or you can SSH into the wordpress directory and use WP-CLI to disable your plugin with following command :-
1) wp plugin list ( to find out all the plugins used by your wordpress)
2) wp plugin deactivate pluginnamehere