Symfony heroku- no home page but api works [closed]

  heroku, php, symfony

I put my api written in symfony on heroku. The application is running and I can use the api, page /api/docs works too, but when I open application, the start page returns:

Oops! An Error Occurred
The server returned a "404 Not Found".
Something is broken. Please let us know what you were doing when this error occurred. We will fix it as soon as possible. Sorry for any inconvenience caused.

and there is no homepage typical for symfony. I found error in logs and its looks like:

Uncaught PHP Exception SymfonyComponentHttpKernelExceptionNotFoundHttpException: "No route found for "GET" (from "")" at /app/vendor/symfony/http-kernel/EventListener/RouterListener.php line 136
2021-10-06T08:57:01.240566+00:00 app[web.1]: 

What could be the problem? this is my .htaccess file:

# Use the front controller as index file. It serves as a fallback solution when
# every other rewrite/redirect fails (e.g. in an aliased environment without
# mod_rewrite). Additionally, this reduces the matching process for the
# start page (path "/") because otherwise Apache will apply the rewriting rules
# to each configured DirectoryIndex file (e.g. index.php, index.html,
DirectoryIndex index.php

# By default, Apache does not evaluate symbolic links if you did not enable this
# feature in your server configuration. Uncomment the following line if you
# install assets as symlinks or if you experience problems related to symlinks
# when compiling LESS/Sass/CoffeScript assets.
# Options +FollowSymlinks

# Disabling MultiViews prevents unwanted negotiation, e.g. "/index" should not resolve
# to the front controller "/index.php" but be rewritten to "/index.php/index".
<IfModule mod_negotiation.c>
    Options -MultiViews

<IfModule mod_rewrite.c>
    RewriteEngine On
    SetEnvIf Authorization "(.*)" HTTP_AUTHORIZATION=$1

    # Determine the RewriteBase automatically and set it as environment variable.
    # If you are using Apache aliases to do mass virtual hosting or installed the
    # project in a subdirectory, the base path will be prepended to allow proper
    # resolution of the index.php file and to redirect to the correct URI. It will
    # work in environments without path prefix as well, providing a safe, one-size
    # fits all solution. But as you do not need it in this case, you can comment
    # the following 2 lines to eliminate the overhead.
    RewriteCond %{REQUEST_URI}::$0 ^(/.+)/(.*)::$
    RewriteRule .* - [E=BASE:%1]

    # Sets the HTTP_AUTHORIZATION header removed by Apache
    RewriteCond %{HTTP:Authorization} .+
    RewriteRule ^ - [E=HTTP_AUTHORIZATION:%0]

    # Redirect to URI without front controller to prevent duplicate content
    # (with and without `/index.php`). Only do this redirect on the initial
    # rewrite by Apache and not on subsequent cycles. Otherwise we would get an
    # endless redirect loop (request -> rewrite to front controller ->
    # redirect -> request -> ...).
    # So in case you get a "too many redirects" error or you always get redirected
    # to the start page because your Apache does not expose the REDIRECT_STATUS
    # environment variable, you have 2 choices:
    # - disable this feature by commenting the following 2 lines or
    # - use Apache >= 2.3.9 and replace all L flags by END flags and remove the
    #   following RewriteCond (best solution)
    RewriteCond %{ENV:REDIRECT_STATUS} =""
    RewriteRule ^index.php(?:/(.*)|$) %{ENV:BASE}/$1 [R=301,L]

    # If the requested filename exists, simply serve it.
    # We only want to let Apache serve files and not directories.
    # Rewrite all other queries to the front controller.
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^ %{ENV:BASE}/index.php [L]

<IfModule !mod_rewrite.c>
    <IfModule mod_alias.c>
        # When mod_rewrite is not available, we instruct a temporary redirect of
        # the start page to the front controller explicitly so that the website
        # and the generated links can still be used.
        RedirectMatch 307 ^/$ /index.php/
        # RedirectTemp cannot be used instead

Source: Symfony Questions