PIngbacks still not working

Hi – I have installed multiple copies of wordpress on self-hosted site. and on all the wordpress blogs the pingbacks are not working. They blogs are neither sending nor receiving picgbacks.

I have checked that the settings under Discusison have those enabled.

I checked the view source and notice that the pingback link has been exposed which when called in a browser works as expected (expect POST only).

The sites have been active for 2 days now. Can someone please help.