garmin cannot update the changes i have made to my email address

Where are you trying to update it? This is the Express forum.

You can change your email address here: Garmin | Account | Profile - it works for me. If it does not work for you, try with another browser, or on an alternative Internet connection, or from another phone or computer. If nothing helps, contact the Support through https://support.garmin.com 

Thank You

I send an email to Garmin because it's impossible to change my profile online