How do I get my security code in without it expiring?

[mesquitebean]

When you go to retrieve your verification code, you must leave the original screen open that asked for the code.  Use a second window or second tab to get the code from your email account.   If you close that first screen, the code will always be seen as expired, since that resets everything.

Another option is to leave that first screen open and use your phone to check your email account for the code.