How do I debug Closed Connection. with SQL State : 08003 SQL Code : 17008

Hello

My application team suddenly is gettgin this erro when using JDBC thin connection

Closed Connection. with SQL State : 08003 SQL Code : 17008

ORA-08003 refers to a sequence which value exceeds its max value, but this doesn't seem to be the case - I checked last_value fo all the sequences in the DB, none of them is close to the max value

There is not mush specifics in the app logfile and no errors in the alert log and trace files.

Any ideas how to debug this?

thank you