[exim] Exim not accepting subaddress (plus style) anymore

Hi all,

I was doing a little physical maintenance to my server this weekend (dust removal, wire cleanup). When I rebooted the machine, it no longer receives mail using subaddress (plus) notation when it was working fine before.

I can still receive mail as just user@mydomain but when I try user+keyword@mydomain I receive a bounceback:

Recipient address rejected: User unknown in virtual alias table

At first I was getting 550 Unrouteable address but I added the following to the userforward section of the config file:

local_part_suffix = +*
local_part_suffix_optional

And now I get the User unknown error.

I'm also using procmail so the router is procmail and the transport is procmail_pipe but my procmail router also contains the same local_part_suffix directives.

I know I'm missing something simple but I can't for the life of me think of what it is now.

Any help would be appreciated, thanks.