Let me provide you some steps on how you can receive the verification code in your email or phone. This way, you can access your account in QuickBooks Online (QBO).
Once you sign in to your QBO account, the system will automatically ask you for a security code. You'll have the option to get the code either by email or phone number to verify it.
If you select to get the code through email and unable to receive it, you can check your spam folder to make sure it hasn't accidentally identified as spam.
If you haven't seen it in the spam folder, then this can be a browser-related issue. Sometimes stored cache in the browser can cause unexpected behavior with the product. You can perform some basic troubleshooting steps to fix it.
First, First, use a private browser to access your account in QuickBooks. It is also known as InPrivate in Internet Explorer and Incognito mode in Google Chrome. This browser mode doesn't record the browsing activity on your local device. You can access this by pressing the following keys:
Press Ctrl + Shift + N (Google Chrome).
Ctrl + Shift + P (Firefox).
Control + Option + P (Safari).
Once done, go back to your email and check the inbox and spam folder. If you're able to receive it, then let's clear the cache in your web browser or try using a different supported browser. This might be a temporary issue with QuickBooks and the current browser that you use.