Cannot convert from varchar to date - sql

Question

I'm trying to make this query work but all the time it gives:
Conversion failed when converting date and/or time from character string.
I've trying make a cast like it show in the code I do not know what else to do
In line 20 there's another idea I had but didn't work either.
SELECT 'Programadas', COUNT(*)
FROM [Base100].[dbo].[HIST_MOVIMIENTO_ENCA] enca
INNER JOIN EHC_FORMATO FORMATO ON FORMATO.CodFormato=ENCA.CodFormato
INNER JOIN [a MEDICO] as medic ON enca.Medico = medic.[número de registro]
INNER JOIN [ESPECIALIDAD] as espc ON medic.especialidad = espc.codigo
INNER JOIN EHC_EVENTODEATENCION eve on enca.NoEvento=eve.noevento
INNER JOIN [a EMPRESA/EPS] eps on eps.nit = eve.empresa
INNER JOIN H_PACIENTE_HOSPITALIZADO HOSP on HOSP.CodigoHospitalizacion=eve.nohospitalizacion
INNER JOIN [a PACIENTE] pac ON HOSP.SecuenciaIngreso = pac.[Secuencia Ingreso]
INNER JOIN H_CAMA C ON HOSP.Habitacion_Cama = C.Habitacion_Cama
INNER JOIN H_HABITACION HAB ON C.Codigo_Hab = HAB.Codigo_Hab
INNER JOIN H_CATEGORIA_HAB CHAB ON HAB.Categoria_Hab = CHAB.Codigo_Categoria
INNER JOIN EHC_ORDENESREALIZADAS ord ON enca.nofolio = ord.nofolio
INNER JOIN EHC_MOVIMIENTODETA MD on MD.nofolio = enca.NoFolio
LEFT JOIN [EHC_ORDENESREALIZADAS] ehcord ON enca.NoFolio = ehcord.nofolio
WHERE FORMATO.CodFormato = 'SPC'
--AND (SELECT CAST(CONVERT(date, CONVERT (varchar(10), MD.respuesta), 103) as date) FROM EHC_MOVIMIENTODETA MD WHERE MD.nofolio = enca.NoFolio AND MD.CodPregunta = 'SPCA2P1')
AND CONVERT(date, SUBSTRING(MD.respuesta, 1,10)) >= CAST(DATEADD(DAY, -1, GETDATE()) as date)
AND MD.CodPregunta = 'SPCA2P1'
AND ord.estado ='P'
AND ehcord.nofolio is null
What I expect it's just the count of the result I know there's no "GROUP BY" but it's ok I just want to know that could be the problem

Answer 1

Use TRY_COVERT it would return NULL without failing the query, so that you can do further investigation on those null returned rows:
Example:
select
TRY_CONVERT (Date, '20190821'), --Success
TRY_CONVERT (Date, '2019 Aug 21'), --Success
TRY_CONVERT (Date, '2019 -Aug- 21'), --Success
TRY_CONVERT (Date, '2019Aug/-21') -- Failed