I think I’ve added the sourceror successfully, however, I still got the error message
Yes you did, however there’s quite a number of warnings as well as you can see. From the sourceror README it reads that they DO support your version of Elixir and OTP, but as a first poke you could try installing fresher versions of each via ASDF package manager (very convenient and supports a lot of tools other than Elixir/OTP). After removing your old installations of Elixir and Erlang and installing ASDF following the instructions on their website:
asdf plugin-add elixir
asdf plugin-add erlang
asdf install erlang 25.3
asdf install elixir 1.14.4-otp-25
asdf global erlang 25.3
asdf global elixir 1.14.4-otp-25
