Czesc Marek,

Maybe upload/replace "error.php" file from raw Helix Ultimate template and compare results.

Yes, inside "folium" folder.

If that will not help , enable Showing Errors MAX + Debug Mode On

I have such errors

Deprecated: Creation of dynamic property HelixUltimateFeatureLogo::$position is deprecated in /md-carport.pl/templates/folium/features/logo.php on line 24

Deprecated: json_decode(): Passing null to parameter #1 ($json) of type string is deprecated in /md-carport.pl/templates/folium/features/logo.php on line 35

Deprecated: Creation of dynamic property HelixUltimateFeatureMenu::$position is deprecated in /md-carport.pl/templates/folium/features/menu.php on line 24

Deprecated: Creation of dynamic property HelixUltimateFeatureContact::$position is deprecated in /md-carport.pl/templates/folium/features/contact.php on line 18

Deprecated: Creation of dynamic property HelixUltimateFeatureFooter::$position is deprecated in /md-carport.pl/templates/folium/features/footer.php on line 18

Deprecated: Creation of dynamic property HelixUltimateFeatureFooter::$load_pos is deprecated in /md-carport.pl/templates/folium/features/footer.php on line 19

Deprecated: Creation of dynamic property HelixUltimateFeatureLogo::$position is deprecated in /md-carport.pl/templates/folium/features/logo.php on line 24

Deprecated: json_decode(): Passing null to parameter #1 ($json) of type string is deprecated in /md-carport.pl/templates/folium/features/logo.php on line 35

Deprecated: Creation of dynamic property HelixUltimateFeatureMenu::$position is deprecated in /md-carport.pl/templates/folium/features/menu.php on line 24

Deprecated: Creation of dynamic property HelixUltimateFeatureSocial::$position is deprecated in /md-carport.pl/templates/folium/features/social.php on line 19

Deprecated: Creation of dynamic property HelixUltimateFeatureSocial::$load_pos is deprecated in /md-carport.pl/templates/folium/features/social.php on line 20

Deprecated: Creation of dynamic property HelixUltimateFeatureTitle::$position is deprecated in /md-carport.pl/templates/folium/features/title.php on line 21

If I give a different template it's ok

Override all files from folder: templates/folium/features/ from Helix Ultimate template package, just override and will be OK in seconds.

It's becuase of using new PHP 8.2

Nothing helped

https://prnt.sc/QFYM-dU7yDFx

For my sites that method always worked.
Have you used files from: helixultimate_template_v2.1.1.zip ??

I cannot login on your site, error 403.

sorry, I made a mistake with the file directory and forgot to remove the restriction,

now I used: helixultimate_template_v2.1.1.zip

the errors are gone

but the 404 still doesn't work

https://md-carport.pl/404

now you should be able to log in

You forgot to override error.php file. Done it by me.

thx