error with mpi fedavg test

[qihuang0]

hi, when I test sh run_step_by_step_example.sh 4 config/mnist_lr/fedml_config.yaml, found below error which cause timeout

and below is my config.yaml

[qihuang0]

but comm_round: 50 and worker_num: 2 , this test is ok

[qihuang0]

the same in other test sh