OSM Access Blocked Referer error affecting OpenLayers and Leaflet

FNC TMS FNC Maps
1

This affects TTMSFNCMaps with Service msOpenLayers or msLeaflet, TTMSFNCOpenLayers and TTMSFNCLeaflet.

Screenshot 2026-03-20 143403
Screenshot 2026-03-20 143403578×557 61.2 KB

We are aware of the issue and are currently investigating possible solutions. Unfortunately, the problem is caused by a breaking change in the OpenStreetMap tileserver, which is the default tileserver used by OpenLayers.

TMS FNC Maps will be updated as soon as a suitable fix has been implemented.

A possible workaround is to configure an alternative tileserver in the TTMSFNCOpenLayers component.

procedure TForm1.TMSFNCOpenLayers1MapInitialized(Sender: TObject);
begin
TMSFNCOpenLayers1.Options.TileServer :=
  'https://{a-c}.basemaps.cartocdn.com/rastertiles/voyager/{z}/{x}/{y}.png';
end;

Note: The suggested tileserver alternative is free for non-commercial use only. For commercial use a paid license is required.

1 Like
3

Any updates on this? Thanks.

Also do you have workaround for tmsfncmaps?

Edit:

For those using ttmsfncmaps the workaround would be something like this:

procedure TfrmServiceRequestMap.TMSFNCMaps1MapInitialized(Sender: TObject);
begin
TMSFNCMaps1.ExecuteJavaScript(
'var newSource = new ol.source.XYZ({' +
' url: ''https://{a-c}.basemaps.cartocdn.com/rastertiles/voyager/{z}/{x}/{y}.png''' +
'});' +
'map.getLayers().getArray()[0].setSource(newSource);'
);
end;

Then make sure to set ttmsfncmaps event OnMapInitialized to TMSFNCMaps1MapInitialized on form create.

4

The issue has been resolved in the latest update of TMS FNC Maps released earlier today.
Please make sure to also update to the latest version of TMS FNC Core.

5

Hi. Just wanted to touch base again. I am now running on windows 10. When I run the compiled EXE the map loads fine and it is fixed, no more referral error. However when I open up that form in the IDE, I get access violation on DispatchMessageW user32.dll. Any idea what is happening?

EDIT:

I fixed it, for people that run into this bug just disable the design time action. DesigntiemEnabled should be false and i don’t get the error.

6

Hi. I do not think it works. I just downloaded and installed Your latest revision of FNC Maps and FNC Core and nothing changed. So it seems that error still exists despite changes in code either I downloaded old version which still is available on my products card.

7

I just made some mistakes. Verified just few minutes ago and here it is. Just downloaded newest versions of FNC Core and FNC Maps, installed FNC Core and during FNC Maps installation (version 4.5.2.0) I have message that FNC Core version is incompatible with installed FNC Maps (requires version 4.2.2.10 of FNC Core). What am I gonna do right now?

8

The latest version of TMS FNC Core is v4.2.3.1, can you please make sure you have that version installed before attempting to install TMS FNC Maps v4.5.2.0?

9

I just discovered older version of FNC Core (4.2.2.10) on my disc and installed it instead of the newest version from TMS download page. And to my suprise everything works fine. Newest version of FNC Maps installs flawlessly and works correctly without displaying previous annoying errors. But anyway newest version of FNC Maps does not work with newest version of FNC Core or at least installer of FNC Maps has a problem with newest version of FNC Core.

10

Yes, I checked that. Now I have two versions (two installers) of FNC Core 4.2.3.1 and 4.2.2.10, and if I install version 4.2.3.1 of FNC Core I have problem with installation of FNC Maps (version 4.5.2.0) which requires version 4.2.2.10 of FNC Core.