There are some restrictions on when you can connect using commitment control. These restrictions also apply to attempting to run statements using commitment control but the connection was established using COMMIT(*NONE).
If a two-phase undetermined or updatable resource is registered or a one-phase updatable resource is registered, another one-phase updatable resource cannot not be registered.
Furthermore, when protected connections are inactive and the DDMCNV job attribute is *KEEP, these unused DDM connections will also cause the CONNECT statements in programs compiled with RUW connection management to fail.
If running with RUW connection management and using the job-level commitment definition, then there are some restrictions.