I am having a similar problem however my radius is 80km (50 miles).
I am receiving some notifications of new caches, but only a few.
I have been having this problem for about three months. Nothing changed in my profile etc at that time.
My email account has not changed, it is not a gmail or yahoo email account. Spam settings are not blocking the notifications. Other Groundspeak communications arrive and as I said some Newly Published caches are coming though. There is no identifying reason as to why those that get sent to me, do
Last week, I reviewed my previous instant notification requests, then deleted them all.
I then set up a whole new suite of instant notifications for published caches (Trad, multi, events etc)
Unfortunately, there have been new caches published very nearby. Unfortunately, I didn't receive notification.
I have forward an enquiry to Groundspeak and am awaiting a reply.
Can anyone help?