Error r2000 "No Observations"

Hello, I am trying to run a mixed effects logistic regression and keep getting error r(2000) "no observations." I have already used the "describe" function and all of my variables are byte or float. Any suggestions on what may be the issue? An example of my do-file command is below

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melogit POSTOP_CIN GENDER MAXDIA_o69 eGFR_u30 AGE RACE BMIreal PREOP_SMOKING HTN DIABETES PRIOR_CABG PRIOR_CAD PRIOR_CHF COPD PRIOR_CVD PREOP_ACE PRIOR_ANEURREP PREOP_ASA PREOP_P2Y PREOP_STATIN PREOP_BETABLOCKER PREOP_ANTICOAG PREOP_MAXAAADIA ILIACANEUR PRIOR_PCI || CENTERID: , or