12c: Non-English Windows: Remote Client connections hang or timeout after a certain number of connec
Something that has caused several SRs to be created recently, is the behavior in a non-English Microsoft Windows environment for 12c.
After a certain number of successful connections (one number is 2049) new Client connections through the listener either hang or results in timeout errors.
Note 1610310.1 "Non-English 12c on Windows: Connections Through Listener Fail After 2049 Attempts" refers
This is related to Bug 17846528 and is scheduled for a fix in the 12.1.0.2 patch set.