When creating maps to display lists of posts as markers you would add a View block to a page to generate the list of posts and then add a Map block, specifying the View as the source for the markers.
Since the 2.0.9 update of Maps, when you try to specify a View as the source the block breaks and displays an error.
You can apply the following patch until an update is available.
Download the zipped file from here: https://toolset.com/patches/toolsetmaps-569.zip
Replace the file map.block.editor.js at wp-content/plugins/toolset-maps/public/js with the unzipped patch.
The fix will be included in the next update of Maps, when it will not be necessary to re-apply the patch.