Hello Florian, Any other error messages before that error happens, e.g. something about the memory. Otherwise, it could be indeed a ulimit issue. First step would be to check the actual configured limits for the kamailio user. Cheers, Henning From: Floimair Florian via sr-users &lt;sr-users(a)lists.kamailio.org&gt; Sent: Montag, 11. November 2024 17:45 To: sr-users(a)lists.kamailio.org Cc: Floimair Florian &lt;f.floimair(a)commend.com&gt; Subject: [SR-Users] Question regarding error message "failed to add new socket to the fd list" Hi! We have recently had issues with one of our Production Kamailios. When those happened, the log was filled with the following message: CRITICAL: <core> [core/tcp_main.c:4528]: handle_new_connect(): failed to add new socket to the fd list Now I wonder what the best approach is to prevent this. We are using TCP/TLS only and I think this might be related to the file ulimit, but I am not sure about that. Shared memory is set to 512MB Can you give me a hint on what to look for? Thank you very much! P.S.: Sorry, I accidentally replied to a previous post of a different topic before which is totally unrelated (I think I should stop working for today 😉) FLORIAN FLOIMAIR Software Development - Symphony Cloud Services Commend International GmbH Saalachstrasse 51 5020 Salzburg, Austria [signature_2072127332] commend.com LG Salzburg / FN 178618z