Could not start a new session. Possible causes are invalid address of the remote server or browser start-up failure

Issues/Bugs
1

package mpappium.Appium;

import java.net.MalformedURLException;
import java.net.URL;

import org.testng.annotations.Test;
import io.appium.java_client.android.AndroidDriver;
import io.appium.java_client.android.options.UiAutomator2Options;

public class Appiumbasic {

@Test
public void Appiumtest() throws MalformedURLException
{
	
	UiAutomator2Options options = new UiAutomator2Options();
	options.setDeviceName("realme RMX1921");
	options.setApp("//Appium//src//main//java//contrs//ApiDemos-debug.apk");
	
	AndroidDriver driver = new AndroidDriver(new URL("http:127.0.0.1:4723"), options);

}
}

2

Hi, you miss double slash
new AndroidDriver(new URL(“http://127.0.0.1:4723”)
after that, check that the Appium server is running properly. and make sure the path specified for the application is correct.