Portal is a fascinating word that means 'portal' or 'gateway'. You don't often hear a sci-fi-esque word like this in a sad love song!
Ivan Cornejo sings, "No sé en dónde encontrar el portal que me llevaba a ti" (I don't know where to find the portal that took me to you). He uses it metaphorically to describe the lost connection to his love, as if he needs to find a magical passage to get back to her, highlighting the immense distance and desperation he feels.
This song is a full-on post-breakup spiral. Ivan Cornejo is completely lost without someone he calls his star, his "estrella." He feels like he's searched the whole galaxy for her, but can't find the "portal que me llevaba a ti" [portal that took me to you]. To see her again, he has to shut the whole world out: turn off the lights, lock the door, switch off his phone, and close his eyes to dream about her. He even admits he started therapy and tried dating other people, but concludes "ninguna te alcanza" [none of them measure up to you].
He seems totally confused about why they even broke up, asking "¿De dónde te salió que ya no me quieras a mí?" [Where did you get the idea that you don't love me anymore?]. He acknowledges they were both stubborn, calling their relationship "una guerra que nunca se termina" [a never-ending war], but he's still desperate. He tries drinking, but finds that "Entre más botellas, sólo te pienso más" [The more bottles, the more I just think of you]. The song ends with him giving up the search, wishing her well from afar: "Donde sea que tú estés / Donde sea, espero estés muy bien" [Wherever you are / Wherever, I hope you're doing very well].