Hello. I would like to ask your help about clogit.
Interventional study was conducted, the data was like as below.

no, age, sex, i.group, pre/post, hypertension
1, 24, F, inter, pre, yes
2, 30, m, control, pre, no
3, 38, f, inter, pre, no

1, 24, F, inter, post, no
2, 30, m, control, post, no
3, 38, f, inter, post,no

I would like to conduct clogit for hypertension presence as binary outcome.

clogit HT age sex i.group, group(no)

But the result was error as below.
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. clogit HT age sex education i.group_co, group(no)
note: multiple positive outcomes within groups encountered.
note: 440 groups (880 obs) dropped because of all positive or
all negative outcomes.
note: age omitted because of no within-group variance.
note: sex omitted because of no within-group variance.
note: education omitted because of no within-group variance.
note: 2.group_co omitted because of no within-group variance.
note: 3.group_co omitted because of no within-group variance.

redundant or inconsistent constraints
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Where was the wrong?
I'm looking forward to your support.
Regards,