If you are not able to connect to any of our IP addresses, the first step would be to check if there are any issues on the networking layer between your terminating equipment and the Infobip equipment.
Ping and telnet commands can help in this case.
It is important to always perform these actions from the source addresses that you're using to access Infobip services (IP addresses).
Please note that the SMPP addresses which you can find in our SMPP API do not accept ping commands, only telnet.
If the issue is not on the networking layer, and you double-checked your configuration, contact our Support team for help with your investigation.