Dear group

This is my first time that I post a question.

Command: qreg Y1 X1 X2 X3, quantile (?)

I run the command for quantile regression above on cross-sectional data. This yields results for quantile (0.1) and upwards to quantile(0.9), but when I specify the 100th quantile (1) -then I get the following error-warning: “VCE computation failed; try a different bandwidth or bsqreg

Could someone perhaps tell me why?
Thank you so much
regards
Pieter