I'm writing a load test script and able to successfully run with 1st request but not able to do 2nd req
I have added the Cookie Manager and tried.The first request is success and 2nd request was failed with timeout
Please help me
Most probably you recorded something which acts like a session identifier and it's hard-coded when it's supposed to be dynamic like when you're logging in you're getting a dynamic parameter which identifies the session.
So you need to perform the correlation of this session identifier.
The easiest way of detecting the dynamic parameters is recording the same user action again and compare the resulting JMeter test plans, all values which have changed need to be correlated - extracted from the previous response using suitable JMeter Post-Processors and stored into JMeter Variables
Once you replace hard-coded dynamic parameters with the respective JMeter Variables you test should start working as expected.
More information: How to Handle Correlation in JMeter