enter image description here

this is my rander log screen

//navbar.ejs
  <% if(!currentUser) {%>
            <a class="nav-link"  href="/signup"><b>Sign Up</b></a>
            <a class="nav-link" href="/login"><b>Log in</b></a>
          <% } %>
          <% if(currentUser) {%>
            <a class="nav-link" href="/logout">Log-out</a>
            <% } %>
//boilerplate
  <%- include("../includes/navbar.ejs") %>
    <div class="container">
        <%- include("../includes/flash.ejs") %>
        <%- body %>
    </div>
//using locals
app.use((req, res, next)=>{
   res.locals.success = req.flash("success");
   res.locals.error = req.flash("error");
   res.locals.currentUser = req.user;
   next();
});

currentUser is using locals and that is req.user
all this working in my local server but when i try to upload this on render this giving me error
why it is giving me error