By using this translation:
https://www.jevents.net/download-area/translation/item/portuguese-language-for-jevents

Many thanks
Tony

Hello, I used this translation and it did not work on joomla 3.9, my language is already configured as PT-BR at the admin and site, however it still does not work.

Hello,

That is our pt-PT language package. Can you use a Joomla! pt-PT language pack? Otherwise, download the one above extract and re-name all files and wording pt-PT to pt-BR and also edit:

pt-PT_JEvents.xml

after renaming to pt-BR and change the same references within the file.

Many thanks
Tony