[senco-forum] email problem

Can anyone explain why I am no longer receiving emails from some people in my address book?  I haven't had any fron senco-forum since before Christmas - I didn't even receive the test I sent, although I know it got through.  Some other people are finding they cannot send me emails either.  Is this likely to be an outlook express problem or my ISP?
All suggestions gratefully received - if they get through!
Thanks
Allison