Well today my friend and I (mostly my friend Ryan) found a strange workaround. We don’t know why the ID is invalid, but is possible to convert the ID into a string and send the string to clients. The strings then can be converted back into ID with the “Create Steam ID From string” node. It worked for us so far but this node’s tooltip only says that it is useful for testing so not sure if it would work 100% all the time. (Engine and Advanced Session Plugin version: 4.26.2)