Using a free public SMS site is a fast track to an immediate account ban.
LinkedIn's security systems aggressively flag these numbers for two main reasons:
- They Detect VoIP and Public Pools: The system easily identifies virtual or VoIP numbers. Public SMS sites use numbers that have already been cycled through thousands of times by spammers and bots, which triggers an automatic red flag.
- The Recovery Trap: Even if you manage to bypass the initial signup, LinkedIn frequently triggers sudden checkpoint verifications. If they lock your account and demand an OTP sent to that exact number a month from now, you will lose the account permanently because that public number will be gone.
If you want to protect your privacy without losing your account, skip the free sites. Instead, use a paid, non-VoIP burner app (like Cloaked, Tossable Digits, or a private Skype/Google Voice number). You get a clean, dedicated number that keeps your personal phone data completely private, but you retain permanent access to it whenever LinkedIn forces a random security check.