Learn Portuguese (Portugal): Os dois palhaços não se dão bem comigo.

This is a lexical-semantic shift. When you add a reflexive pronoun to dar, it completely changes meaning. The reflexive verb dar-se, when followed by bem (well) or mal (poorly), means "to get along". Without the se, the verb would simply mean "to give".

Why does the reflexive pronoun se come before the verb as não se dão?

The negative word não acts as a "magnet" in European Portuguese. It forces the pronoun to move in front of the verb instead of attaching to the end with a hyphen. If the sentence were positive, it would be Os dois palhaços dão-se bem comigo.

Why is the word comigo used instead of com mim?

The expression dar-se bem requires the preposition com to specify who you get along with. In Portuguese, the preposition com combined with the pronoun mim (me) always fuses into the single irregular word comigo.

Can I use dar-se bem to talk about things other than relationships with people?

Yes! A great B2-level use of this reflexive verb is to describe how you tolerate environments, climates, or foods. For example, you can say Não me dou bem com o calor to mean "I don't do well with the heat" or "The heat doesn't agree with me".