[bitfolk] Issues receiving e-mails from BT Internet customers

Hi all, I run an e-mail server on one of my BitFolk VPSs. It seems fine except for one oddity which has arisen lately. Some e-mails from BT Internet customers take of the order of 3 weeks to arrive. Looking at the headers, they move around between a couple of BT server to begin with, then sit on the final one for up to 3 weeks before they are delivered to my server. I can see no failed earlier attempts to deliver in my logs, and my server receives e-mails fine from everyone else - just BT seems to be the problem, and not even all the e-mails coming from BT. Anyone else seen anything like this or can suggest a likely explanation? In case it's of relevance, BT's delivery still seems to be IPv4 only. My server advertises both IPv6 and IPv4 addresses. Cheers, John -- Xronos Scheduler - https://xronos.uk/ All your school's schedule information in one place. Timetable, activities, homework, public events - the lot Live demo at https://schedulerdemo.xronos.uk/