Hitting REST API from postman and android application has different behavior

Question

when I hit API form POSTMAN, I am able to get the response. But when I hit using code, "Android app using Retrofit", I am getting following error: "java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.".

I had tried below options to resolve the issue.

1. manifest : android:usesCleartextTraffic="true" & android:networkSecurityConfig="@xml/network_security_config" 2.network_security_config.xml

<network-security-config> xmlns:android="http://schemas.android.com/apk/res/android">
    <base-config cleartextTrafficPermitted="true" />
</network-security-config>

3. using certificate: taken ref from internet: object HttpClient { // Create a trust manager that does not validate certificate chains val unsafeOkHttpClient: OkHttpClient

   // Install the all-trusting trust manager

    // Create an ssl socket factory with our all-trusting manager
    get() = try {
        // Create a trust manager that does not validate certificate chains
        val trustAllCerts: Array<TrustManager> = arrayOf<TrustManager>(
            object : X509TrustManager {
                @Throws(CertificateException::class)
                override fun checkClientTrusted(
                    chain: Array<X509Certificate?>?,
                    authType: String?
                ) {
                }
   
                @Throws(CertificateException::class)
                override fun checkServerTrusted(
                    chain: Array<X509Certificate?>?,
                    authType: String?
                ) {
                }
   
                override fun getAcceptedIssuers(): Array<X509Certificate?>? {
                    return arrayOf()
                }
   
                /* override fun getAcceptedIssuers(): Array<X509Certificate> {
                    TODO("Not yet implemented")
                }*/
   
                /* val acceptedIssuers: Array<X509Certificate>
                     get() =  arrayOf(_AcceptedIssuers)*/
            }
        )
   
        // Install the all-trusting trust manager
        val sslContext: SSLContext = SSLContext.getInstance("SSL")
        sslContext.init(null, trustAllCerts, SecureRandom())
   
        // Create an ssl socket factory with our all-trusting manager
        val sslSocketFactory: SSLSocketFactory = sslContext.getSocketFactory()
        val builder = OkHttpClient.Builder()
        builder.sslSocketFactory(sslSocketFactory, trustAllCerts[0] as X509TrustManager)
        builder.hostnameVerifier(object : HostnameVerifier {
            override fun verify(hostname: String?, session: SSLSession?): Boolean {
                return true
            }
        })
            .connectTimeout(1, TimeUnit.MINUTES)
            .readTimeout(30, TimeUnit.SECONDS)
            .writeTimeout(15, TimeUnit.SECONDS)
        builder.build()
    } catch (e: Exception) {
        throw RuntimeException(e)
    }
   

} I am able to hit the API and get the response. Can someone tell me why Server is asking for Certificate while hitting the API from code?

Thanks in advance.