UserWarning: [Errno 12] Cannot allocate memory. joblib will operate in serial mode

Hey, I am getting the below error while try to run more than 6 instance of rasa

/usr/local/lib/python3.6/dist-packages/sklearn/externals/joblib/_multiprocessing_helpers.py:38: UserWarning: [Errno 12] Cannot allocate memory.  joblib will operate in serial mode
  warnings.warn('%s.  joblib will operate in serial mode' % (e,))
2023-04-19 09:24:06 INFO     absl  - Entry Point [tensor2tensor.envs.tic_tac_toe_env:TicTacToeEnv] registered with id [T2TEnv-TicTacToeEnv-v0]
terminate called after throwing an instance of 'std::system_error'
  what():  Resource temporarily unavailable
Aborted

These are the bot instance running to my server:

Although I checked my ram usage and there I have space available.

This is the screenshot of my RAM When 6 rasa instance is running:

python version: 3.6.9 rasa version-: 1.4.3

Thanks in advance