DESeq2 error in design~ code

Hi everyone
I need to run Deseq2, but when I try to run this part of command the following error message appears.

Error in DESeqDataSet(se, design = design, ignoreRank) : 
  design has a single variable, with all samples having the same value.
  use instead a design of '~ 1'. estimateSizeFactors, rlog and the VST can then be used
De plus : Warning message:
In DESeqDataSet(se, design = design, ignoreRank) :
  1 duplicate rownames were renamed by adding numbers 

I am new to R and DESeq2, Please anyone could hepl me to fix this error. Thank you very much