Cause
An attempt was made to alter the sessions parameter in the root container or non-consolidated database.
An attempt was made to alter the sessions parameter in the root container or non-consolidated database.
The sessions parameter behaves like a static parameter in root containers and non-consolidated databases and hence cannot be altered. It can only be altered from a pluggable database.
Try the following links for this error:
http://docs.oracle.com/cd/E16655_01/server.121/e26079/e0.htm
https://community.oracle.com/message/1193289
https://community.oracle.com/message/1117811
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