Please try to set up your Guest Wi-Fi again after resetting your router to factory setting.
 

Here are two ways of how to reset. Please select only one:

•   On the Mercku App: Select the main router > Press Factory Reset button on the bottom of the page.

•   Press the reset button on the bottom of the M2, wait for 5 seconds until the indicator light is blinking red. Please do not hold the reset button for longer.

 

Please contact support@mercku.com if the reset did not fix the issue.