Cannot connect to host rasa_worker

When I trained on the train model error message will appearing “Training Failed” “Your model training has failed”. After I inspect the Developer Tools → Network in the browser following error message highlighted

{“version”:“0.41.2”,“status”:“failure”,“message”:“Failed to train a Rasa model.”,“reason”:“StackTrainingFailed”,“details”:“Cannot connect to host rasa-worker:5005 ssl:default [Temporary failure in name resolution]”,“help”:null,“code”:500}