Why is the registration of smart vocational education always wrong or expired by SMS?

Smart vocational education can't register and fill in the verification code just issued, and remind you of errors or expiration at any time. There is no error in entering the verification code, but an error is still prompted, which may be the following two situations:

2.

The problem of refreshing the page will change the login verification code every time the page is refreshed. If you are prompted that the verification code is wrong, the system will replace the verification code. At this point, the page may still be the previous verification code, and you cannot enter the same verification code twice.