2FA code works sometimes and fails sometimes

Intermittent 2FA failures on X (formerly Twitter) are usually timing or sync issues, not random bugs.

Most common reasons (in short):

• Device time not synced → TOTP codes depend on exact time (even 30–60 sec drift breaks it)
• Using multiple devices/apps → codes from different authenticators can mismatch
• Code expiry delay → entering near the end of the 30-sec window
• Network latency (web login) → request reaches server after code expires
• Backup method confusion → SMS vs authenticator vs email
• Browser session issues (since your web login already has problems)

Quick fixes that actually work:

• Turn on automatic date & time sync on your phone
• Always enter the code immediately after it refreshes
• Stick to one authenticator app (like Google Authenticator or Microsoft Authenticator)
• Try login on mobile → then web (session carryover sometimes helps)
• Disable VPN while logging in
• Re-scan/reset 2FA if issue persists

Important insight:
Since your mobile works but web fails, this strongly suggests:

Web login delay + expiring TOTP = intermittent failure