TNS-12535: TNS: operation timed out
‘nt secondary err code: 60’ , which indicates that from the Windows OS TCP/IP layer has been raised a timeout , which has been translated under Oracle in these informational messages.
Operating system level:
Check that there is no firewall blocking the traffic on port 1521
The TNS-12535 or ORA-12535 error is commonly a timeout error associated with Firewalls or slow Networks.
Check incorrect “timeout” parameter setting for the following files:
sqlnet.expiry_time = 0 (indefinite time)
sqlnet.expiry_time increase the time limit for the connectivity.
Note: TNS-12170/ ORA-12170 at connection time
Least chance is that slow connections to the database
You can used parameter PRE_PAGE_SGA for increased the process startup duration. not recommended to set.
Every process when starts must access page in the SGA. Solution for TNS-12170/ ORA-12170 at connection time