If a message is displayed in the center display, take appropriate action (in a calm manner) according to the displayed message.

KEY Warning Light (Some models)
Stop Vehicle in Safe Place ImmediatelyMazda 6 Owners Manual: To Resume Cruising Speed at More Than 25 km/h (16 mph)
If some other method besides the OFF/ CANCEL switch was used to cancel cruising
speed (such as applying the brake pedal) and the system is still activated, the
most recent set speed will automatically resume when the RESUME/
switch is pressed.
If vehicle speed is below 25 km/h (16 mph), incre ...
Mazda 6 Owners Manual: Immobilizer system reprogram procedure
Note
When an error occurs during the reprogram procedures, except when
the PCM is replaced, repeat the procedure from Step 1. If you still cannot
reprogram, confirm how many keys can start the engine. Then, perform the key
replacement or addition reprogram procedure according to the val ...