Can't connect simple Android sketch to running emulator. Why?

Windows 10 PC running processing 3.2.1. Added Android Mode via configuration manager. Created new sketch, switched to Android Mode and entered simple code from "Rapid Android Development":

void setup() { size(400,400); }

void draw() { ellipse(mouseX, mouseY, mouseX-pmouseX, mouseY-pmouseY); }

Compilation proceeds normally, emulator (5566:Processing-0253) pops up then console writes this:

Error type 2

android.util.AndroidException: Can't connect to activity manager; is the system running?

at com.android.commands.am.Am.onRun(Am.java:376)

at com.android.internal.os.BaseCommand.run(BaseCommand.java:51)

at com.android.commands.am.Am.main(Am.java:121)

at com.android.internal.os.RuntimeInit.nativeFinishInit(Native Method)

at com.android.internal.os.RuntimeInit.main(RuntimeInit.java:262)

The key phrase is "activity manager" which, I assume, would have normally started up when compilation finished and the emulator initialized.

Thanks for any tips...