promocionalesbbase.com presents itself as a login portal for something called Banco Base's promotional catalog, with a Spanish-language interface and an email address referencing bancobase.com. But there's a big difference between linking to a bank's name and being operated by that bank.
A legitimate financial service portal would typically show its legal entity name, have a published privacy policy and terms of use, and make it easy to find a physical address or customer support phone number. This site has none of those things. The owner's identity is hidden behind a privacy service, and the only way to reach someone is a single email address mentioned in the sign-in text.
If you're wondering whether promocionalesbbase.com is a scam or fake, the safest answer is that there isn't enough trustworthy information to prove it's legitimate. For any site asking you to log in, especially one that looks like it connects to a bank, the absence of basic transparency is a serious red flag. Don't enter your credentials until you can independently verify that this site is actually run by Banco Base.