Message Oracle ORA-29338 - datafile string is in an undesired state (string, string)

ERRORdatafile string is in an undesired state (string, string)
CAUSEThe referred datafile is not in a state ready for tablespace copy operation. For example, the datafile may be offline. The datafile needs to be ONLINE, and either READ ONLY or READ WRITE.
ACTIONPut the datafile into the desired state.