fetchnews only storing one message

I am running fetchnews -vvv to collect new messages. It finds a number
to retrieve

uk.net.news.config: receiving article 250396 (1536 more up in the air)
.storing <g+CELzuqX+BNNAhm@...>: uk.net.news.config

And that's it: it only stores one article. It will do this every time
I run the command, with the "up in the air" count decrementing by one
each iteration.

It worked until today, all I have changed is to increase maxage.

Any idea why this happens?

Thanks

Guy