This has now come up twice, and we wanted to put it on record in case it should ever occur again. Comcast apparently has 1&1, our e-mail/online shop provider, flagged as a source of spam and doesn't accept file attachments from 1&1 IP addresses.
We've raised a support enquiry with 1&1, who say that it's 'an intermittent problem'. This is all very well, and in the most recent case we did manage to get the file through eventually, but frankly it makes us look as if we're not doing our job - and that's not a situation we're particularly happy with.
Readers who have Comcast accounts need to be aware that there may be some difficulty in completing your order. We'll keep trying, of course, and we'll do our best to communicate with you about it, but in exceptional cases we may need to find an alternative method of delivering your file. Meanwhile, if you have a second account with another provider - anyone who isn't Comcast! - it might be easier all round if you were to order your book(s) from there.
Just a thought!