Check your device settings first. Go to network settings and switch airplane mode on for 10 seconds, then off again. This forces your phone to reconnect to the nearest tower. If drops continue, reset network settings entirely. On iPhone: Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. On Android: Settings > System > Reset options > Reset Wi-Fi, mobile & Bluetooth. You'll need to re-enter saved Wi-Fi passwords afterward.
Clear your browser cache and cookies completely. Press Ctrl+Shift+Delete (Cmd+Shift+Delete on Mac), select all time periods, check both cache and cookies boxes. Try logging in through incognito mode first. If that works, the issue was cached data. Still failing? Request a password reset link. Sometimes accounts get temporarily locked after multiple failed attempts. Wait 15 minutes before trying again.
Tower maintenance might be ongoing. Test with another device using Telefonica SIM in the same location. If other device works fine, your handset needs attention. Check for carrier settings updates in phone settings. Make sure you haven't accidentally selected manual network selection instead of automatic. Dial your network code manually if automatic fails.
Contact your bank first. Many card issuers block telecom payments as fraud prevention. Whitelist Telefonica merchant codes with your bank. Try alternative payment methods: direct debit setup takes 2-3 days but eliminates card issues. Check if your card supports international transactions if you're roaming. Prepaid cards often have restrictions on recurring payments.