Reducing 40 MHz Harmonics in ESP8266 (ESP-07) During EMC Testing—Hardware or Software?

Hi, I have a device in a metal enclosure (mainly the antenna sticks out) with an ESP8266 module (ESP-07) that I recently sent for electromagnetic testing.
In response, I got the message that when measuring the radiated emission in the GTEM chamber from about 300 MHz onwards, pins appear on the spectrum at a spacing of exactly every 40 MHz.
I am a complete layman when it comes to such tests.
What can I do to reduce these 40 MHz harmonics? Any hardware modifications? Or software ones?

Include a schematic, PCB view, test report - diagram, what design treatments you have now applied to reduce emissions. ?

Suggesting that the ESP-07 module uses 40 MHz flash memory, I replaced this module with the ESP-07S module.
The new device is already undergoing testing. I am closing the topic.