Refused Diners Club Airport Lounge access - anyone else been refused entry recently?

Was travelling round Europe September last year where most airports have a lounge(s) that accept Diners Club for free access

At two different airports (Catania and Birmingham Intl) was refused entry at the lounges that do accept Diners.  After a lot of haggling at Catania, managed to finally get in at the grace of the door b..tch (but at Birmingham, no chop).  

On both occasions the lounges weren't full and both had clear signage that Diners was accepted.

Has anyone else experienced anything similar?


On what basis did they say they were refusing entry?

In both locations when they swiped the card the system errored out with an “access denied” message, this happened for all 3 of us using different diners club cards.