Which encryption is recommended for own messenger I wrote my own messaging-app and now I would like to encrypt the data transfer between my client (app) and my server. What kind of encryption is easy to implement and can be recommended? I am very very knew to the whole encryption thing. I would love to get some hints or ideas as input.

I use TCP/IP for delivering the messages.
TLS, without a doubt. Note that TLS does not imply HTTP, so you can use it with whatever TCP protocol you have.

For UDP you can use DTLS, which I believe forces the use of CTR mode to combat packet loss.