If there is a firewall, check that the filtering has been set correctly. If the server is the sender in the environment where multiple IP addresses are assigned to one NIC, the packet sender will be an IP address assigned to the physical interface. Therefore, if you use a virtual IP address to communicate through the firewall, set the filter so that the physical IP address can also go through the firewall. For details, see "F.3.5 Unable to communicate using virtual IP addresses after configuring a firewall".
Similarly, if you have created the settings so that the communication target does not allow a physical IP address using the filtering function, change the settings so that the physical IP address is allowed.
Confirmation method
Check the filtering settings for the firewall and the communication target.
