E-mails going directly to Blacklist folder but I acnnot find details of sender to remove

Some of my e-mails appear as blacklisted but when I open rules/blacklist I cannot find them in the list

Hi Alan, what do you mean by appear as blacklisted? Are they in the SPAM folder or just marked (categorized) as SPAM?
This can be caused by the spam filter on your server as well.

Thank you,