Multiple VU in Jmeter-Only one user able to insert data

Test Plan:-

1.User logs in

2.Enter details in a form and save it(Which is stored in DB)

3.Logs out

When ran with 2 Virtual User

Number Of Threads(user) = 2

Ramp Up Period = 1 Loop Count = 1

Only 1 user is able to successfully store the details in DB

2nd Thread/user gives some url in response instead of JSON Data

When used one thread and script is ran many times it is successfully storing data in DB

Elements used:-

HTTP Cookie Manager

View Result Tree

Am I missing some element ? What mistake i am doing ?