How do I get rid of the periodic need to enter a security code?

How do I get rid of the periodic need to enter a security code?

A few months ago I decided to take advantage of the additional security whereby if a different browser is used to access Zoho mail, the system texts you a security code which you must then enter before you are allowed into Zoho mail.  I'm finding this to be a real pain in the neck -- it happens every time I delete cookies, and even if I don't, it happens once a month as a matter of course.  Sometimes have to go get my cell phone at an inopportune time.  How do I get rid of this feature?