Test code succeeds in sandbox, and fails in production test after deployment

•     Setup-àDevelop --> Apex Text Execution
•     Checked Disabled Parallel Apex Testing

•   Clicked the link "View Test History" ( Clear Test Results.)

• SetupàDevelop --> Apex Classes-àClicked "Compile all classes"
•  Click On "Estimate your organization's code coverage" 
• Clicked Run All Tests 
•  Run  Apex tests again. 

Governor Limit in Salesforce:

Salesforce runs on a multitenant environment which means resources (Storage, CPU, Memory) are shared with other companies on the Salesforce platform. This means limits must be in place to ensure that all companies using the Salesforce architecture abide by certain rules and don’t let their code or processes monopolize shared resources.