I have a bug with celery i can't solve. when I send an async job that get data from various APIs and write all in a DB, in the case of lot there is lot of data

I have a bug with celery i can't solve. when I send an async job that get data from various APIs and write all in a DB, in the case of lot there is lot of data, the celery task finish properly to but my flask app becomes unresponsive. I have to restart flask to get back to a normal state. Anyone would know where I should check?