The fnd_conflicts_domain table has reached the max rows of 25K. So Conflict resolution manager was not able to pick new requests.
We manually deleted the records using
delete from applsys.fnd_conflicts_domain a
where not exists
(select 1 from applsys.fnd_concurrent_requests b
where b.cd_id = a.cd_id and Phase_code <> 'C')
and cd_id <> 0 and dynamic = 'Y';
after that the sytem came to normal.
Thanks for Sharing the solution...
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