400 Client Error

I am getting this error
400 Client Error: Bad Request for url: https://services.sentinel-hub.com/ogc/wms/20e4ee00-1a1c-4b0c-MASKED?SERVICE=wms&WARNINGS=False&MAXCC=50.0&Transparent=True&ShowLogo=False&BBOX=32.6094%2C130.3802%2C33.0025%2C130.8813&FORMAT=image%2Ftiff&CRS=EPSG%3A4326&TIME=2019-11-23T02%3A08%3A22%2F2019-11-23T02%3A08%3A22&WIDTH=2352&HEIGHT=2180&LAYERS=BLUE&REQUEST=GetMap&VERSION=1.3.0

I wonder what is the source of error? when i even type “https://services.sentinel-hub.com”, i get 503 Service Unavailable. No server is available to handle this request.

You get an error nicely described:
<ServiceException code="LayerNotDefined"> Layer BLUE not found </ServiceException>

So it is very simple - your configuration does not have “BLUE” layer within.
If you replace “BLUE” with e.g. “1_TRUE_COLOR”, you will get results.

For the “503” - there is no service at that address - you need to add /ogc at the end.