# -*- coding: utf-8 -*-
from django.shortcuts import render, redirect
from django.contrib.auth.decorators import permission_required
from django.core.mail import send_mail

from .forms import FeedbackForm


def add(request):
    data = request.POST if request.POST else None
    if request.POST:
        form = FeedbackForm(data)
        if form.is_valid():
                form.save()
                feedback = form.instance
                name = feedback.name
                email = feedback.email
                information = feedback.information
                send_mail(u"Обратна връзка",
                        u"Подател: {} {} информация: {}".format(name, email, information),
                        "diaphanum.fmi@gmail.com",
                        ["diaphanum.fmi@gmail.com"])
                return redirect('members:user-projects')
    else:
        form = FeedbackForm()

    return render(request, 'feedback/add_form.html', {'feedback_form': form})

# -*- coding: utf-8 -*-
from django.shortcuts import render, redirect
from django.contrib.auth.decorators import permission_required
from django.core.mail import send_mail

from .forms import FeedbackForm


def add(request):
    data = request.POST if request.POST else None
    form.errors['captcha'] = "Опитайте отново"
    if request.POST:
        form = FeedbackForm(data)
        if form.is_valid():
                form.save()
                feedback = form.instance
                name = feedback.name
                email = feedback.email
                information = feedback.information
                send_mail(u"Обратна връзка",
                        u"Подател: {} {} информация: {}".format(name, email, information),
                        "diaphanum.fmi@gmail.com",
                        ["diaphanum.fmi@gmail.com"])
                return redirect('members:user-projects')
    else:
        form = FeedbackForm()

    return render(request, 'feedback/add_form.html', {'feedback_form': form})

Change error message