The PM feature hasn't been working for some time, most can't send/receive so it's not just you.
FYI, this format we use here and love for our swap is very old software*, trying to run on a much newer internet, that Paul is basically holding together with double sticky tape and mirrors to keep running here. Problems with the PM feature is a symptom of that.
PMs did work over on the newer format/swap, but that swap generally wasn't used.
*Which is no longer supported/updated by the company that created it.