# AT commands ESP8266 gives Null Pointer error - Arduino IDE

EDIT: I have just tried a brand new esp8266 and the AT commands work. But on 3 others it did not. Would this be because I have uploaded code to them?

I have an esp8266 ES01, the small basic one. I am connecting to the Arduino IDE 1.8.15 via a USB module, with a soldered toggle-switch across the pins to allow it to be in flash mode or not.

I am able to successfully upload the blink code example from the arduino IDE and it works, the LED blinks. I can also send text from the esp8266 via the serial and can read it in the arduino IDE.

But I cant seem to connect to it via any AT commands "AT" or "AT+GMR". I have tried Baud 9600 and 115200 but keep getting an error message.

Any ideas what I would have to do to connect? or why there would be an error? If i try it with the switch in the opposite position it sends, but I get nothing back.

at processing.app.Serial.write(Serial.java:254)
at processing.app.Serial.write(Serial.java:274)
at processing.app.SerialMonitor.send(SerialMonitor.java:122)
at processing.app.SerialMonitor.lambda$new$1(SerialMonitor.java:66)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348) at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402) at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252) at java.awt.Component.processMouseEvent(Component.java:6539) at javax.swing.JComponent.processMouseEvent(JComponent.java:3324) at java.awt.Component.processEvent(Component.java:6304) at java.awt.Container.processEvent(Container.java:2239) at java.awt.Component.dispatchEventImpl(Component.java:4889) at java.awt.Container.dispatchEventImpl(Container.java:2297) at java.awt.Component.dispatchEvent(Component.java:4711) at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4904) at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4535) at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4476) at java.awt.Container.dispatchEventImpl(Container.java:2283) at java.awt.Window.dispatchEventImpl(Window.java:2746) at java.awt.Component.dispatchEvent(Component.java:4711) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:760) at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709) at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74) at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:84)
at java.awt.EventQueue$4.run(EventQueue.java:733) at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain\$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:730)