When using Sysmac Studio and entering an IP-address with 1 or 2 digit parts in your Structured Text or ladder code make sure to use leading underscores.

For example if you want to address a device at IP-address 192.168.250.15 then in your code it should read 192.168.250._15

Not using the leading underscore or adding zeros will result in no connection.

If an IP-address is applied through a string variable written through the variable view window or by any other means (like from an NS Terminal) you can use the normal notation. eg. 192.168.250.15