Google Search Console zeigt plötzlich viele Error 500 an

Die Website scheint ganz normal zu funktionieren, aber seit ein paar Tagen zeigt die Google Search Console bei „Smartphone“ eine ganze Menge Serverfehler an (http error 500)

Ich habe an der Installation nichts geändert und es wurden auch keine automatischen Updates gemacht.

Wordpress 4.9.8, Thema: Donovan
Debian Stretch, PHP 7.0

Was könnte dafür die Ursache sein?

Hier eine Liste der fehlerhaften Seiten:

wp-includes/class-feed.php
wp-includes/class-http.php
wp-includes/class-IXR.php
wp-includes/class-simplepie.php
wp-includes/class-snoopy.php
wp-includes/class-walker-category-dropdown.php
wp-includes/class-walker-category.php
wp-includes/class-walker-comment.php
wp-includes/class-walker-nav-menu.php
wp-includes/class-walker-page-dropdown.php
wp-includes/class-walker-page.php
wp-includes/class-wp-customize-control.php
wp-includes/class-wp-customize-panel.php
wp-includes/class-wp-customize-section.php
wp-includes/class-wp-customize-setting.php
wp-includes/class-wp-feed-cache.php
wp-includes/class-wp-http-ixr-client.php
wp-includes/class-wp-http-requests-hooks.php
wp-includes/class-wp-http-requests-response.php
wp-includes/class-wp-image-editor-gd.php
wp-includes/class-wp-image-editor-imagick.php
wp-includes/class-wp-simplepie-file.php
wp-includes/class-wp-simplepie-sanitize-kses.php
wp-includes/class-wp-text-diff-renderer-inline.php
wp-includes/class-wp-text-diff-renderer-table.php
wp-includes/class-wp-user-meta-session-tokens.php
wp-includes/class-wp-xmlrpc-server.php
wp-includes/class.wp-scripts.php
wp-includes/class.wp-styles.php
wp-includes/customize/class-wp-customize-background-image-control.php
wp-includes/customize/class-wp-customize-background-image-setting.php
wp-includes/customize/class-wp-customize-background-position-control.php
wp-includes/customize/class-wp-customize-code-editor-control.php
wp-includes/customize/class-wp-customize-color-control.php
wp-includes/customize/class-wp-customize-cropped-image-control.php
wp-includes/customize/class-wp-customize-custom-css-setting.php
wp-includes/customize/class-wp-customize-date-time-control.php
wp-includes/customize/class-wp-customize-filter-setting.php
wp-includes/customize/class-wp-customize-header-image-control.php
wp-includes/customize/class-wp-customize-header-image-setting.php
wp-includes/customize/class-wp-customize-image-control.php
wp-includes/customize/class-wp-customize-media-control.php
wp-includes/customize/class-wp-customize-nav-menu-auto-add-control.php
wp-includes/customize/class-wp-customize-nav-menu-control.php
wp-includes/customize/class-wp-customize-nav-menu-item-control.php
wp-includes/customize/class-wp-customize-nav-menu-item-setting.php
wp-includes/customize/class-wp-customize-nav-menu-location-control.php
wp-includes/customize/class-wp-customize-nav-menu-locations-control.php
wp-includes/customize/class-wp-customize-nav-menu-name-control.php
wp-includes/customize/class-wp-customize-nav-menu-section.php
wp-includes/customize/class-wp-customize-nav-menu-setting.php
wp-includes/customize/class-wp-customize-nav-menus-panel.php
wp-includes/customize/class-wp-customize-new-menu-control.php
wp-includes/customize/class-wp-customize-new-menu-section.php
wp-includes/customize/class-wp-customize-sidebar-section.php
wp-includes/customize/class-wp-customize-site-icon-control.php
wp-includes/customize/class-wp-customize-theme-control.php
wp-includes/customize/class-wp-customize-themes-panel.php
wp-includes/customize/class-wp-customize-themes-section.php
wp-includes/customize/class-wp-customize-upload-control.php
wp-includes/customize/class-wp-widget-area-customize-control.php
wp-includes/customize/class-wp-widget-form-customize-control.php
wp-includes/default-filters.php
wp-includes/default-widgets.php
wp-includes/embed-template.php
wp-includes/feed-atom-comments.php
wp-includes/feed-atom.php
wp-includes/feed-rdf.php
wp-includes/feed-rss.php
wp-includes/feed-rss2-comments.php
wp-includes/feed-rss2.php
wp-includes/functions.php
wp-includes/ID3/module.audio-video.asf.php
wp-includes/ID3/module.audio-video.flv.php
wp-includes/ID3/module.audio-video.matroska.php
wp-includes/ID3/module.audio-video.quicktime.php
wp-includes/ID3/module.audio-video.riff.php
wp-includes/ID3/module.audio.ac3.php
wp-includes/ID3/module.audio.dts.php
wp-includes/ID3/module.audio.flac.php
wp-includes/ID3/module.audio.mp3.php
wp-includes/ID3/module.audio.ogg.php
wp-includes/ID3/module.tag.apetag.php
wp-includes/ID3/module.tag.id3v1.php
wp-includes/ID3/module.tag.id3v2.php
wp-includes/ID3/module.tag.lyrics3.php
wp-includes/IXR/class-IXR-clientmulticall.php
wp-includes/IXR/class-IXR-introspectionserver.php
wp-includes/locale.php
wp-includes/media.php
wp-includes/ms-default-filters.php
wp-includes/ms-settings.php
wp-includes/nav-menu-template.php
wp-includes/registration-functions.php
wp-includes/registration.php
wp-includes/Requests/Auth/Basic.php
wp-includes/Requests/Exception/HTTP.php
wp-includes/Requests/Exception/HTTP/304.php
wp-includes/Requests/Exception/HTTP/305.php
wp-includes/Requests/Exception/HTTP/306.php
wp-includes/Requests/Exception/HTTP/400.php
wp-includes/Requests/Exception/HTTP/401.php
wp-includes/Requests/Exception/HTTP/402.php
wp-includes/Requests/Exception/HTTP/403.php
wp-includes/Requests/Exception/HTTP/404.php
wp-includes/Requests/Exception/HTTP/405.php
wp-includes/Requests/Exception/HTTP/406.php
wp-includes/Requests/Exception/HTTP/407.php
wp-includes/Requests/Exception/HTTP/408.php
wp-includes/Requests/Exception/HTTP/409.php
wp-includes/Requests/Exception/HTTP/410.php
wp-includes/Requests/Exception/HTTP/411.php
wp-includes/Requests/Exception/HTTP/412.php
wp-includes/Requests/Exception/HTTP/413.php
wp-includes/Requests/Exception/HTTP/414.php
wp-includes/Requests/Exception/HTTP/415.php
wp-includes/Requests/Exception/HTTP/416.php
wp-includes/Requests/Exception/HTTP/417.php
wp-includes/Requests/Exception/HTTP/418.php
wp-includes/Requests/Exception/HTTP/428.php
wp-includes/Requests/Exception/HTTP/429.php
wp-includes/Requests/Exception/HTTP/431.php
wp-includes/Requests/Exception/HTTP/500.php
wp-includes/Requests/Exception/HTTP/501.php
wp-includes/Requests/Exception/HTTP/502.php
wp-includes/Requests/Exception/HTTP/503.php
wp-includes/Requests/Exception/HTTP/504.php
wp-includes/Requests/Exception/HTTP/505.php
wp-includes/Requests/Exception/HTTP/511.php
wp-includes/Requests/Exception/HTTP/Unknown.php
wp-includes/Requests/Exception/Transport.php
wp-includes/Requests/Exception/Transport/cURL.php
wp-includes/Requests/Hooks.php
wp-includes/Requests/Proxy/HTTP.php
wp-includes/Requests/Response/Headers.php
wp-includes/Requests/Transport/cURL.php
wp-includes/Requests/Transport/fsockopen.php
wp-includes/rest-api/class-wp-rest-response.php
wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
wp-includes/rest-api/endpoints/class-wp-rest-post-statuses-controller.php
wp-includes/rest-api/endpoints/class-wp-rest-post-types-controller.php
wp-includes/rest-api/endpoints/class-wp-rest-posts-controller.php
wp-includes/rest-api/endpoints/class-wp-rest-revisions-controller.php
wp-includes/rest-api/endpoints/class-wp-rest-settings-controller.php
wp-includes/rest-api/endpoints/class-wp-rest-taxonomies-controller.php
wp-includes/rest-api/endpoints/class-wp-rest-terms-controller.php
wp-includes/rest-api/endpoints/class-wp-rest-users-controller.php
wp-includes/rest-api/fields/class-wp-rest-comment-meta-fields.php
wp-includes/rest-api/fields/class-wp-rest-post-meta-fields.php
wp-includes/rest-api/fields/class-wp-rest-term-meta-fields.php
wp-includes/rest-api/fields/class-wp-rest-user-meta-fields.php
wp-includes/rss-functions.php
wp-includes/rss.php
wp-includes/script-loader.php
wp-includes/session.php
wp-includes/SimplePie/Cache/DB.php
wp-includes/SimplePie/Cache/File.php
wp-includes/SimplePie/Cache/Memcache.php
wp-includes/SimplePie/Cache/MySQL.php
wp-includes/SimplePie/Core.php
wp-includes/template-loader.php
wp-includes/theme-compat/comments.php
wp-includes/theme-compat/embed-404.php
wp-includes/theme-compat/embed-content.php
wp-includes/theme-compat/embed.php
wp-includes/theme-compat/footer-embed.php
wp-includes/theme-compat/footer.php
wp-includes/theme-compat/header-embed.php
wp-includes/theme-compat/header.php
wp-includes/theme-compat/sidebar.php
wp-includes/update.php
wp-includes/vars.php
wp-includes/widgets/class-wp-nav-menu-widget.php
wp-includes/widgets/class-wp-widget-archives.php
wp-includes/widgets/class-wp-widget-calendar.php
wp-includes/widgets/class-wp-widget-categories.php
wp-includes/widgets/class-wp-widget-custom-html.php
wp-includes/widgets/class-wp-widget-links.php
wp-includes/widgets/class-wp-widget-media-audio.php
wp-includes/widgets/class-wp-widget-media-gallery.php
wp-includes/widgets/class-wp-widget-media-image.php
wp-includes/widgets/class-wp-widget-media-video.php
wp-includes/widgets/class-wp-widget-media.php
wp-includes/widgets/class-wp-widget-meta.php
wp-includes/widgets/class-wp-widget-pages.php
wp-includes/widgets/class-wp-widget-recent-comments.php
wp-includes/widgets/class-wp-widget-recent-posts.php
wp-includes/widgets/class-wp-widget-rss.php
wp-includes/widgets/class-wp-widget-search.php
wp-includes/widgets/class-wp-widget-tag-cloud.php
wp-includes/widgets/class-wp-widget-text.php
wp-includes/wp-diff.php