You should run Seafile 8.0 with Python3.6+. At the same time, you need to check whether Django-2.2.14.dist-info exists in the seafile-server-latest/seahub/thirdpart directory, Django2.2.14 is already included in the Seafile installation package.
From the 7.1.0 version, Seafile will depend on Python 3 and is not compatible with Python 2, and Seafile 8.0 must be run using Django 2.2.x.