[BUGFIX] Fallback to default language within internal linking suggest…

…ions if All Languages is selected, changed language error message

CHANGELOG.md

@@ -7,7 +7,7 @@ We will follow [Semantic Versioning](http://semver.org/).
 
 ## UNRELEASED
 ### Fixed
-- Show warning on linking suggestions when content element is set to "All Languages" instead of fatal exception
+- Show warning on linking suggestions when the language cannot be retrieved from the content element, use the default language in case "All Languages" is selected
 - Added extra checks within the metatag generators in case fields do not exist (opengraph, twitter, robots)
 - `hasSitemapFields` now correctly returns the `sitemapFields` instead of `yoastSeoFields`
 

Classes/Form/Element/InternalLinkingSuggestion.php

@@ -102,6 +102,10 @@ protected function getLocale(int $pageId): ?string
         $siteFinder = GeneralUtility::makeInstance(SiteFinder::class);
         try {
             $site = $siteFinder->getSiteByPageId($pageId);
+            if ($this->languageId === -1) {
+                $this->languageId = $site->getDefaultLanguage()->getLanguageId();
+                return $site->getDefaultLanguage()->getTwoLetterIsoCode();
+            }
             return $site->getLanguageById($this->languageId)->getTwoLetterIsoCode();
         } catch (SiteNotFoundException|\InvalidArgumentException $e) {
             return null;

Resources/Private/Language/BackendModule.xlf

@@ -197,7 +197,7 @@
 				<source>Unable to determine linking suggestions.</source>
 			</trans-unit>
 			<trans-unit id="tx_yoastseo_linking_suggestions.languageError" resname="tx_yoastseo_linking_suggestions.languageError">
-				<source>This content element does not have a language to analyze.</source>
+				<source>There was a problem retrieving the language information for this content element, check your site configuration.</source>
 			</trans-unit>
 
 			<trans-unit id="page" xml:space="preserve">