Probpem with plugin migration from 2.1 -> 2.2

Hello,
I have created my own checks with additional pagest to confirm configuration changes.
My check monitro existence of phisical boards in device, detect any change in configuration, and report it as a error until acknowledged.
It works fine in my existing 2.1.0p44 version of checkmk, but I can’t update to version 2.2.
I have created file in local/share/checkmk/web/plugins/icons to create additional icon in context menu to accept changes and another local/share/checkmk/web/plugins/pages where user can see changes and confirm them.
When using version 2.2.0p46 - my ‘acknowlkedge’ postion exists in context menu, but afer activating it I have typical Apache ‘not found’ page. Whwre is the problem? How can I debug this kind of files? There is no entries in var/log/web.log file.

My icon plugins file: local/share/checkmk/web/plugins/icons/boards.py:

from cmk.gui.utils.urls import makeuri_contextless
from cmk.gui.http import request, response
@icon_and_action_registry.register
class boardsIcon(Icon):
    @classmethod
    def ident(cls):
        return boards"
    @classmethod
    def title(cls) -> str:
        return _("boards")
    def service_columns(self):
        return ["host_name", "service_description", "check_command"]
    def render(self, what, row, tags, custom_vars):
        if what != "service" or row[what + "_check_command"] not in [
            "check_mk-boards",
        ]:
            return
        sitename, hostname, item = row["site"], row["host_name"], row["service_description"]
        url = makeuri_contextless(
            request,
            [("site", sitename), ("host", hostname), ("file", item)],
            filename="boards",
        )
        return "accept", _("acknowledge configuration changess"), url

My page file at local/share/checkmk/web/plugins/pages/board.py

#!/usr/bin/env python3
import datetime
import time
from collections.abc import Iterator
from cmk.gui.breadcrumb import (
    Breadcrumb,
    BreadcrumbItem,
    make_current_page_breadcrumb_item,
    make_simple_page_breadcrumb,
)
from cmk.gui.htmllib.header import make_header
from cmk.gui.htmllib.html import html
from cmk.gui.http import request
from cmk.gui.i18n import _
from cmk.gui.logged_in import user
from cmk.gui.main_menu import mega_menu_registry
from cmk.gui.page_menu import (
    make_display_options_dropdown,
    make_simple_link,
    PageMenu,
    PageMenuDropdown,
    PageMenuEntry,
    PageMenuTopic,
)

@cmk.gui.pages.register("boards")                                                                                                                                                                                                                                                                                                                                    
def page_show():                                                                                                                                                                                                                                                                                                                                                         
    service = request.var("file")
    host_name = request.var("host", "")
    title = _("hardware configuration changes")                                                                                                                                                                                                                                                                                                                      
    breadcrumb = make_simple_page_breadcrumb(mega_menu_registry.menu_monitoring(), title)                                                                                                                                                                                                                                                                                
    make_header(html, title, breadcrumb, conf_page_menu(breadcrumb))                                                                                                                                                                                                                                                                                                 
    html.h1 ("Test!!!")                                                                                                                                                                                                                                                                                                                                                  
    html.footer ()                                                                                                                                                                                                                                                                                                                                                       
    return            
    
def conf_page_menu(breadcrumb: Breadcrumb) -> PageMenu:
    return PageMenu(
        dropdowns=[
            PageMenuDropdown(
                name="cfg_errs",
                title=_("Configuration changes"),
                topics=[
                    PageMenuTopic(
                        title=_("Acknowledge"),
                        entries=list(conf_acknowledge()),
                    ),
                ],
            ),
        ],
        breadcrumb=breadcrumb,
    )

def conf_acknowledge(
) -> Iterator[PageMenuEntry]:
    yield PageMenuEntry(
        title="Configuraton changesa",
        icon_name="accept",
        item=make_simple_link(
            make_confirm_link(
                url=makeactionuri(request, transactions, [("func", "1")]),
                message=_("Do you really want to acknowledge new configration?")
            )
        ),
        is_shortcut=True,
        is_suggested=True,
    )