Sometimes problems will cause a page to load slowly. As there are so many issues that can cause the problem it's impossible to pinpoint a solution without a lot of information beforehand. If you are about to contact your host or support executive try and avoid assuming they will know everything about your website, it's code and how you have configured it. As you can imagine this problem is unlikely to be the responsibility of any single individual. Here is one method to help find the core reason for the problem.
Is it just one visitor experincing the problem?
If they tell you the whole site is slow and you don't experience the same then the problem is likely to be at their end and therefore little you can do about it.
If it's a particular page then login as them and try for yourself. If they are correct, then try another user. If no other login experiences the problem then you have a strange issue! Some things to look at is people do not see their own banners and web pages, therefore it could be that someone has placed something in rotation that is causing the slow down.
Mod Security
Mod Security (mod_sec) is a common cause of odd problems. These are rules created by your host to protect you against all kinds of malicious attacks. Unfortunately many of them will also block friendly traffic. There is little you can do except ask your host to disable it for your site (your host is unlikely to create seperate rules for each site on your server). They may say YOU can disable it though the .htaccess, for more information see MOD_SEC Issues.
Is it just you that experiences the issue?
If accessing a particular page in the BCP is the problem it could be an issue with the config.inc.php, the database or mod_security (see above). Make sure you take a full backup before investigating these issues. An extra copy of the config.inc.php is always adviseable.
If the slow down occured just after making changes to the configuration of the script then take a backup of the config.inc.php and restore the previous version. If that fixes the issue then you know the previous change was the issue and know where to start your investigation.
The Database
Perhaps the most common cause for a slow down is the database. Following is a busy traffic exchange and demonstrates the performance of the BCP login. If your login experience is slow in comparison then check the tracking tables are cut regularly and if any tables are corrupt (Check General Maintenance & Assistance in the video training library)