The application server could not being contacted

From the PostgreSQL 9.6 upgrade to the PostgreSQL 10 use of the process, in the past pgAdmin 3 there have been a lot of problems, not fully supported PostgreSQL 10 .
pgAdmin 4Experience poor, very bad even, the key is the postgresql-10.3-1-windows-binaries compression version of the pgAdmin 4 failure to start, the start of the time will report the following error message:
The application server could not be contacted
Workaround: Create an empty venv\lib\site-packages\backports directory under the __init__.py

cd pgAdmin 4type nul > venv\lib\site-packages\backports\__init__.py

Reference: http://blog.csdn.net/pierian_d/article/details/79510309

The application server could not being contacted