Do not change the user map query in the Portal template
Your edit attempt in
is based on a false assumption. This is absolutely not a wikilink for MediaWiki, but a Semantic MediaWiki query about category properties (inside "#ask").
Do not change that query, it has its own syntax defined by Semantic MediaWiki. That syntax performs an union of members in several categories (using || here is a documented standard syntax for "#ask" queries; it is NOT reparsed by MediaWiki, only parsed by the "#ask" parser function managed by Semantic MediaWiki). It is correct, and has always queried users of the language having knowledge levels N (native), 5 (professional) and 4 (advanced). This query is shared across all language portals.
Your edit attempted to fix something that is NOT incorrect, but had the undesired effect to restrict the returned users list to get ONLY native speakers. Since ever, it has also included professional and advanced speakers. --- Addition: do not remove the map as you did in the template. It has been there since very long and for all language portals. If you don't understand the syntax or how this works, please ask. But there's absolutely nothing wrong in the map displayed in Portal:Sr for the Serbian language. Note that this map has limitations, and cannot show users that don't have reagistered their location in their user page, and since ever it limits the results to users that have indicated speaking Serbian natively, professionnalyn, or with an advanted level, so users listed from 3 categories are shown on the map (this is the same for all languages).
Additional users may be found in the categories linked in the sample "babelbox" shown in the portal, or at bottom of the portal, these categories contain more users (including those that have not indicated their geographic location on their user page, and users that speak/write/read Serbian with lower levels).