AMP script error with conditional statement "The initial end count value for the for loop could not be cast to an integer."

Question

I'm getting the error

The subscriber preview failed to generate. Review the details, correct all issues, and try again. The initial end count value for the for loop could not be cast to an integer.

when trying to go to preview and test in marketing cloud

%%[
 var @rows, @rowCount, @vendedorEmail
    set @vendedorEmail = Email
    set @rows = LookupRows("felipevendedores", "Email", @vendedorEmail)
    set @rowCount = rowcount(@rows)
]%%


     %%[
     IF @rowCount > 0 THEN
 
     FOR @i = 1 TO @rowCount DO
     set @row = ROW(@rows,@i)
 
     var @contactId, @clientName, @clientEmail 
     set @contactId = FIELD(@row,'ContactId') 
     set @clientName= field(@row,"Nome_Cliente") 
     set @clientEmail = field(@row,"Email_Cliente")
     
     set @celular = field(@row,"Celular_Cliente") 
         IF EMPTY(@celular) THEN 
         set @celular = 'Não informado'
     ENDIF ]%%

Answer 1

Looks like you're missing and endif and next @i. I'd suggest you wrap your send context assignments with AttributeValue.

%%[ 

    set @vendedorEmail = AttributeValue("Email")
    set @rows = LookupRows("felipevendedores", "Email", @vendedorEmail) 
    set @rowCount = rowcount(@rows) 

]%%

%%[

 IF @rowCount > 0 THEN

    FOR @i = 1 TO @rowCount DO

         set @row = ROW(@rows,@i)
         set @contactId = FIELD(@row,'ContactId') 
         set @clientName= field(@row,"Nome_Cliente") 
         set @clientEmail = field(@row,"Email_Cliente")
         set @celular = field(@row,"Celular_Cliente") 

         IF EMPTY(@celular) THEN 
            set @celular = 'Não informado'
         ENDIF

]%%
  <!-- HTML HERE -->
%%[

    next @i 

endif

]%%