thanks for your interest in my problem. The situation happens to many MS and I think it take place in whole our network.
“If this MS (MS 1) calls someone, does it work ? if few minutes later you try to call that MS (MS 1), can you go through ?”
If MS1 calls to someone than the call is successful. And if someone calls to MS1 the call is successful.
The vendor of our equipment is Ericsson.