Backend error. 400 Bad Request

2019-03-18 16:42:00,165 -- pyeikon -- DEBUG -- Request:{'Entity': {'E': 'DataGrid', 'W': {'instruments': ['0#SFC:'], 'fields': [{'name': 'RECORDTYPE'}]}}, 'ID': '123'} 

2019-03-18 16:42:18,681 -- pyeikon -- DEBUG -- HTTP Response code: 200 

2019-03-18 16:42:18,681 -- pyeikon -- DEBUG -- HTTP Response: {"ErrorCode":400,"ErrorMessage":"Backend error. 400 Bad Request"} 

2019-03-18 16:42:18,681 -- pyeikon -- ERROR -- Backend error. 400 Bad Request 

2019-03-18 16:42:18,698 -- pyeikon -- DEBUG -- Request:{'Entity': {'E': 'DataGrid', 'W': {'instruments': ['0#SFC:'], 'fields': [{'name': 'RECORDTYPE'}]}}, 'ID': '123'} 

2019-03-18 16:42:20,173 -- pyeikon -- DEBUG -- HTTP Response code: 200 

2019-03-18 16:42:20,173 -- pyeikon -- DEBUG -- HTTP Response: {"columnHeadersCount":1,"data":[["/.FTXIN9",118],["/SFCH9",114],["/SFCJ9",114],["/SFCK9",114],["/SFCM9",114],["/SFCU9",114],["/SFCZ9",114],["/SFCH0",114]],"headerOrientation":"horizontal","headers":[[{"displayName":"Instrument"},{"displayName":"RECORDTYPE","field":"RECORDTYPE"}]],"rowHeadersCount":1,"totalColumnsCount":2,"totalRowsCount":9} 

Is the common reason for Error 400? This was a very first request today, so it's not about any limit.