
                    For bootstrap4, we pick up the best solutions provided by github life savers.
                    If google brings you here, you are so lucky! These life savers are angels, they have well solved your problems.
                    So do not waste time scrolling the original issue threads just to dig out solutions... 
                    Here you are, you are welcome. Then, go back to work!
                    

Or you can create a file named postcss.config.js in root directory Just leave it empty or write the following line 

ngx admin No PostCSS Config found with build:prod

FYI if you are using this solution check out my other reply:
#1375 (comment)
I couldn't get this to work 

ngx admin Add JWT automatically for every HTTP request

Temporary solution for that In your bower.json:
startbootstrap-sb-admin-2: https://github.com/BlackrockDigital/startbootstrap-sb-admin-2.git#master, 

startbootstrap sb admin 2 Problem when i try to install startbootstrap-sb-admin-2 with bower

I'm going to add the Cross-Origin-Resource-Policy: cross-origin in production later today I have #1496 which will check for the header in all the CDN files. 

bootstrapcdn Consider asserting a Cross-Origin-Resource-Policy?

@gitwith we don't add bootstrap.min.css.map to /latest/ Please choose /3.3.7/ I was just investigating this issue on stackoverflow http://stackoverflow.com/questions/35142485/why-is-bootstrap-trying-to-load-less-files-in-ie-edge/35151109#35151109 and it became apparent that the less files declared in the bootstrap.min.css.map file are 403'ing
This is currently breaking SourceMap debugging in browser tools such as Edge and Chrome F12 tools.