help in : -- TNS - 12519 TNS: no appropriate service handler found

Today , I am facing this issue (TNS - 12519  TNS: no appropriate service handler found) and search to resolve it , my oracle database information :

Oracle Database Enterprise Edition .

Version : 11.2.0.4

Platform : Win server 2012  64-bit

Ram : 32 GB

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When Return To Log I found These Error :

ORA-00020: maximum number of processes (2000) exceeded

Before My Process is 1560 ;

Then I changed it To 2000 And Restart My Database , Then I face That Error Again .

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I need any help Today Pl z.

With My best Regards ,,,