Buzón literally means "mailbox" or "postbox." However, in modern Spanish, especially in the context of phone calls, it's commonly used to refer to "voicemail."
In the song, Gera MX repeatedly says, "Pediré perdón por mandar a buzón" (I'll ask for forgiveness for sending to voicemail). This phrase perfectly captures the artist's struggle to balance his demanding career with his personal relationships, as he's often too busy to answer calls and has to let them go to voicemail.
Gera MX's "A Mis Amigos" is a heartfelt letter to old friends, family, and even a romantic interest, reflecting on how much his life has changed since becoming a successful artist. He opens by describing his humble beginnings, composing music "Debajo de alguna escalera" [Under some stairs], and how he's now reached great heights but is "aun así sigo subiendo" [still climbing].
He expresses regret for not being around, saying "Mi carrera sí me ausenta" [My career does make me absent] and apologizes for sending calls to voicemail: "Pediré perdón por mandar a buzón" [I'll ask for forgiveness for sending to voicemail]. He's often busy with concerts, giving his "última canción" [last song], or doing interviews. Gera MX misses his friends, noting that "El Ren está en Australia, Rencko casi ni lo veo" [Ren is in Australia, I barely see Rencko], and remembers simpler times, like "Tirar humo en ese parque era un verdadero paseo" [Smoking in that park was a real stroll]. Despite the fame and the demands on his time, he never forgets where he came from, even recalling "aquellos días que no comimos" [those days we didn't eat]. It's a raw and honest look at the sacrifices made for a dream, all while holding onto the love for those who never abandoned him: "Salud por la familia que nunca me abandonó" [Cheers to the family that never abandoned me].