Cause
Trying to login more than once from different processes for ORACLE started in single-process mode.
Trying to login more than once from different processes for ORACLE started in single-process mode.
Logoff from the other process.
Try the following links for this error:
http://docs.oracle.com/cd/E16655_01/server.121/e26079/e0.htm
https://community.oracle.com/message/9273960
https://community.oracle.com/message/977906
https://community.oracle.com/message/977247
https://community.oracle.com/message/9446075
https://community.oracle.com/message/2025568
https://community.oracle.com/message/1193289
https://community.oracle.com/message/4497062
https://community.oracle.com/message/1117811
https://community.oracle.com/message/1228927
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