Either direct Tp calls and gw/no_reg_con_info is set too high without a physical default file, or hard coding as suggested by Bernhard.
Or your transport routes / groups are too complicated and which system the message is coming from is not included in the message.
I place my bets of transport groups as that seems to be the latest fashion to centralize support of developments, authorizations and TMS passwords (and Z-object names) which then collide and produce messages in application pings even (SM59 -> Test -> Authorization Test)
Cheers,
Julius