Lula's supporters responded by sharing his messages through a 10-million-strong WhatsApp group to bypass the algorithms.
The Trump-Lula relationship may have thawed, but several issues could reignite tensions between the two leaders.
Lula wins fourth term in dramatic Brazil election comeback If that sounds muddled, it is because the relationship between the two men is not straightforward.
But Lula's defiance against what he has described as US interference in Brazilian affairs evoked a patriotic spirit that proved an effective campaigning tool.
Whether that lasts will depend on how far the US tries to intervene in Brazilian affairs, and how bullish Lula is in response.
Even some in the agricultural lobby, typically strong Bolsonaro supporters but reliant on US trade, thought Lula had a point.
When I spoke to Lula at his residence about a year ago, relations had hit rock bottom.
But Trump was a close ally of Flávio's father, the former President Jair Bolsonaro.
Paradoxically, it seems to have earned him President Donald Trump's respect.
It is a sensitive subject for a political left that remembers the region's brutal 20th Century dictatorships, many backed by the CIA in the name of stopping communism.