Can't PM one member

[HorTs]

When I type in the name of the user or select send PM from their profile. I get the following message when I press send.

The following error or errors occurred while posting this message:

    * One or more 'to'-recipients could not be found.

Does anyone have any ideas?

[Illori]

does the member still exist in the database? did they delete their account? are you sure you are spelling their user name correctly?

[HorTs]

They are definitily still active, they can send PMs but when you reply it gives that error too.

[Illori]

do they have any special characters in their name? any non-english characters on an english forum?

[HorTs]

The user's name is Green 4's. PMs have worked previously.

[Brettflan]

With the apostrophe? That could definitely do it. SMF doesn't normally allow those in usernames, so I'm guessing you converted from another forum system which did allow them.
Try changing his display name to remove the apostrophe (or replace it with a variant of the normal apostrophe) and then try sending another PM to him, that should take care of it.

EDIT: alternately, you could replace the apostrophe in his display name with a backtick ("`", on same key as tilde "~") or similar character.

[Deaks]

HorTs, did brettflans suggestions work?

[HorTs]

Yes, thanks to all those who suggested solutions.