Unable to access Acumatica Rest API

I’m not able to access the Acumatica API, through Postman and also Power Automate 

Tried with both OAuth2.0 and Standard Authentication.

I’ll paste the sample below - 

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curl --location 'http://23.19.244.91/AcumaticaERP/entity/Default/20.200.001/Customer?%24select=CustomerName&%24top=10'

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"message": "An error has occurred.",

    "exceptionMessage": "Execution Timeout Expired.  The timeout period elapsed prior to completion of the operation or the server is not responding.",

    "exceptionType": "PX.Data.PXDatabaseException"

"innerException": {

            "message": "An error has occurred.",

            "exceptionMessage": "The wait operation timed out",

            "exceptionType": "System.ComponentModel.Win32Exception",

            "stackTrace": null

        }

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I was able to access them before, and It's been above 6 days this issue has started.

Also, could you please provide me with a solution to increase the performance of Acumatica web