Choose sign-in, not registration
At the destination, select the option for an existing account. Read the identifier field: a display name is not always the same as a registered phone number or username. The service’s current form has not been verified here, so use the fields it actually displays.
Check saved details before resetting
Autofill may select an older password or a different saved account. Review that choice and remove accidental spaces. If you genuinely do not know the password, use the reset process offered by the account provider rather than trying many guesses.
When a verification message is missing
Look at the contact destination and any countdown displayed. Requesting several codes quickly can make it difficult to tell which one is current. If you no longer control the registered phone or email, contact the account provider about recovery rather than sending a code to a third party. If you can sign in but a payment is missing, compare the two records described in deposit help.