I tried a simpe code to display a list of contacts in vfpage

public class Payment {
public List<Contact> ls{get;set;}
public Set<String> st{get;set;}
public string str{get;set;}


    public Payment(){
    List<Contact> ls = new List<Contact>();
    ls = [select id, name from contact limit 3];
    Set<String> st = new Set<String>();
    st.add('1111111');
    st.add('addad');
    st.add('gxghdy');
    st.add('6366vx');
    str = '123';
    
    }
}

<apex:page controller="Payment">
    {!ls}{!st}{!str}
    <apex:pageBlock >
        <apex:pageBlockTable value="{!ls}" var="a">
            <apex:column value="{!a.name}"/>
        </apex:pageBlockTable>
    </apex:pageBlock>
</apex:page>

checked all sharing settings every thing is public
this is my new dev edition signedup today
i had same issue with one signed up this month
is this a bug or an issue with my code

--- I can see contacts in debug logs
 

I want to host my website on salesforce and found these limits but i was confused that Maximum Pageviews limit is per hour or per month.