Why all observations are "on support" on propensity score matching?

Hi I'm doing propensity score matching for reducing selection bias in observational study.

There was significant difference between PPI exposure group and PPI non-exposure group in comorbidity.

So I performed propensity score matching, setting the independent variable as a "PPI_exposure" and the other covariates as Age, sex, HTN, DM, Dyslipidemia.

I wanted to PSM 1:1 but there was no off supp, and all observation were on support.

How can I fix this problem?

Code:

 psmatch2 PPI_3W Age Sex HTN DM Dyslip , out(CCI) noreplacement

Probit regression                               Number of obs     =      4,557
                                                LR chi2(5)        =      81.84
                                                Prob > chi2       =     0.0000
Log likelihood =   -1434.54                     Pseudo R2         =     0.0277

------------------------------------------------------------------------------
      PPI_3W |      Coef.   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
         Age |   .0183717   .0023795     7.72   0.000      .013708    .0230355
         Sex |   .0379768   .0532516     0.71   0.476    -.0663945    .1423481
         HTN |   .0402486   .0552818     0.73   0.467    -.0681018    .1485989
          DM |   .0723273   .0599909     1.21   0.228    -.0452527    .1899072
      Dyslip |   .0814611   .0548364     1.49   0.137    -.0260163    .1889385
       _cons |  -2.601975   .1722587   -15.11   0.000    -2.939596   -2.264354
------------------------------------------------------------------------------
----------------------------------------------------------------------------------------
        Variable     Sample |    Treated     Controls   Difference         S.E.   T-stat
----------------------------+-----------------------------------------------------------
             CCI  Unmatched |  1.1986755   .884015595   .314659902   .046942343     6.70
                        ATT |  1.1986755   1.02207506   .176600442   .067535405     2.61
----------------------------+-----------------------------------------------------------
Note: S.E. does not take into account that the propensity score is estimated.

           | psmatch2:
 psmatch2: |   Common
 Treatment |  support
assignment | On suppor |     Total
-----------+-----------+----------
 Untreated |     4,104 |     4,104 
   Treated |       453 |       453 
-----------+-----------+----------
     Total |     4,557 |     4,557 


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