Open and proces a sentinel 2 product with BEAM (visat 5.0)?

Is it possible to use the program BEAM for processing sentinel 2 products?

No, it is not. The format is not supported in BEAM.
Why do you want to use it?

thank you!

It is because i want to make a chlorophyll map and i know how to make it with BEAM.

I now tried with SNAP. I resampled the file but with processing in snap an error keeps occuring.
A org.esa.snap.core.gpf.OperatorException exception has occurred.

I probably do something wrong. Is there maybe a solution?

You should see more as only the org.esa.snap.core.gpf.OperatorException.
Please have a look in the log file. Go to Help / Open Log Directory and in the messages.log file you should see more information after the exception occurred.
Also it would be good to know how which operator you have used. The FUB/WeW? This one can’t process S2 data yet.