How to correct the problem with the acute accent HTML

sorry if it's a repeated question.

I work with a web system, and it happens that on a page, when I put accent on a user's name, it breaks.

Exemple: https://imgur.com/lWzqRy4

Can you help me, please?

I validated the charset, meta.

I expect the output Luís. But the actual output is LuÃs, with this exemple https://imgur.com/lWzqRy4