diff --git a/src/Model/GContact.php b/src/Model/GContact.php
index 95afc1be6e..bd2d14064e 100644
--- a/src/Model/GContact.php
+++ b/src/Model/GContact.php
@@ -28,6 +28,7 @@ use Friendica\Core\Logger;
 use Friendica\Core\Protocol;
 use Friendica\Core\System;
 use Friendica\Core\Search;
+use Friendica\Core\Worker;
 use Friendica\Database\DBA;
 use Friendica\DI;
 use Friendica\Network\Probe;
@@ -1275,6 +1276,75 @@ class GContact
 		}
 	}
 
+	/**
+	 * Fetches the followers of a given profile and adds them
+	 *
+	 * @param string $url URL of a profile
+	 * @return void
+	 */
+	public static function discoverFollowers(string $url)
+	{
+		$apcontact = APContact::getByURL($url);
+
+		if (!empty($apcontact['followers']) && is_string($apcontact['followers'])) {
+			$followers = ActivityPub::fetchItems($apcontact['followers']);
+			Logger::info('Discover AP followers', ['url' => $url, 'contacts' => count($followers)]);
+			foreach ($followers as $follower) {
+				if (DBA::exists('gcontact', ['nurl' => Strings::normaliseLink(($follower))])) {
+					continue;
+				}
+				Logger::info('Discover new AP contact', ['url' => $follower]);
+				Worker::add(PRIORITY_LOW, 'UpdateGContact', $follower);
+			}
+			Logger::info('AP followers discovery finished', ['url' => $url]);
+		}
+
+		if (!empty($apcontact['following']) && is_string($apcontact['following'])) {
+			$followings = ActivityPub::fetchItems($apcontact['following']);
+			Logger::info('Discover AP followings', ['url' => $url, 'contacts' => count($followings)]);
+			foreach ($followings as $following) {
+				if (DBA::exists('gcontact', ['nurl' => Strings::normaliseLink(($following))])) {
+					continue;
+				}
+				Logger::info('Discover new AP contact', ['url' => $following]);
+				Worker::add(PRIORITY_LOW, 'UpdateGContact', $following);
+			}
+			Logger::info('AP followings discovery finished', ['url' => $url]);
+		}
+
+
+		$data = Probe::uri($url);
+		if (empty($data['poco'])) {
+			return;
+		}
+
+		$curlResult = Network::curl($data['poco']);
+		if (!$curlResult->isSuccess()) {
+			return;
+		}
+		$poco = json_decode($curlResult->getBody(), true);
+		if (empty($poco['entry'])) {
+			return;
+		}
+
+		Logger::info('PoCo Discovery started', ['url' => $url, 'contacts' => count($poco['entry'])]);
+
+		foreach ($poco['entry'] as $entries) {
+			if (!empty($entries['urls'])) {
+				foreach ($entries['urls'] as $url) {
+					if ($url['type'] == 'profile') {
+						if (DBA::exists('gcontact', ['nurl' => Strings::normaliseLink(($url['value']))])) {
+							continue;
+						}
+						Logger::info('Discover new PoCo contact', ['url' => $$url['value']]);
+						Worker::add(PRIORITY_LOW, 'UpdateGContact', $$url['value']);
+					}
+				}
+			}
+		}
+		Logger::info('PoCo Discovery finished', ['url' => $url]);
+	}
+
 	/**
 	 * Returns a random, global contact of the current node
 	 *
diff --git a/src/Module/Admin/Site.php b/src/Module/Admin/Site.php
index ec6f01afa0..078f169299 100644
--- a/src/Module/Admin/Site.php
+++ b/src/Module/Admin/Site.php
@@ -178,6 +178,7 @@ class Site extends BaseAdmin
 		$optimize_max_tablesize = (!empty($_POST['optimize_max_tablesize']) ? intval(trim($_POST['optimize_max_tablesize'])) : 100);
 		$optimize_fragmentation = (!empty($_POST['optimize_fragmentation']) ? intval(trim($_POST['optimize_fragmentation'])) : 30);
 		$poco_completion        = (!empty($_POST['poco_completion'])        ? intval(trim($_POST['poco_completion']))        : false);
+		$gcontact_discovery     = (!empty($_POST['gcontact_discovery'])     ? intval(trim($_POST['gcontact_discovery']))     : false);
 		$poco_requery_days      = (!empty($_POST['poco_requery_days'])      ? intval(trim($_POST['poco_requery_days']))      : 7);
 		$poco_discovery         = (!empty($_POST['poco_discovery'])         ? intval(trim($_POST['poco_discovery']))         : PortableContact::DISABLED);
 		$poco_discovery_since   = (!empty($_POST['poco_discovery_since'])   ? intval(trim($_POST['poco_discovery_since']))   : 30);
@@ -305,6 +306,7 @@ class Site extends BaseAdmin
 		DI::config()->set('system', 'optimize_max_tablesize', $optimize_max_tablesize);
 		DI::config()->set('system', 'optimize_fragmentation', $optimize_fragmentation);
 		DI::config()->set('system', 'poco_completion'       , $poco_completion);
+		DI::config()->set('system', 'gcontact_discovery'    , $gcontact_discovery);
 		DI::config()->set('system', 'poco_requery_days'     , $poco_requery_days);
 		DI::config()->set('system', 'poco_discovery'        , $poco_discovery);
 		DI::config()->set('system', 'poco_discovery_since'  , $poco_discovery_since);
@@ -669,6 +671,7 @@ class Site extends BaseAdmin
 			'$optimize_fragmentation' => ['optimize_fragmentation', DI::l10n()->t('Minimum level of fragmentation'), DI::config()->get('system', 'optimize_fragmentation', 30), DI::l10n()->t('Minimum fragmenation level to start the automatic optimization - default value is 30%.')],
 
 			'$poco_completion'        => ['poco_completion', DI::l10n()->t('Periodical check of global contacts'), DI::config()->get('system', 'poco_completion'), DI::l10n()->t('If enabled, the global contacts are checked periodically for missing or outdated data and the vitality of the contacts and servers.')],
+			'$gcontact_discovery'     => ['gcontact_discovery', DI::l10n()->t('Discover followers/followings from global contacts'), DI::config()->get('system', 'gcontact_discovery'), DI::l10n()->t('If enabled, the global contacts are checked for new contacts among their followers and following contacts.')],
 			'$poco_requery_days'      => ['poco_requery_days', DI::l10n()->t('Days between requery'), DI::config()->get('system', 'poco_requery_days'), DI::l10n()->t('Number of days after which a server is requeried for his contacts.')],
 			'$poco_discovery'         => ['poco_discovery', DI::l10n()->t('Discover contacts from other servers'), (string)intval(DI::config()->get('system', 'poco_discovery')), DI::l10n()->t('Periodically query other servers for contacts. You can choose between "Users": the users on the remote system, "Global Contacts": active contacts that are known on the system. The fallback is meant for Redmatrix servers and older friendica servers, where global contacts weren\'t available. The fallback increases the server load, so the recommended setting is "Users, Global Contacts".'), $poco_discovery_choices],
 			'$poco_discovery_since'   => ['poco_discovery_since', DI::l10n()->t('Timeframe for fetching global contacts'), (string)intval(DI::config()->get('system', 'poco_discovery_since')), DI::l10n()->t('When the discovery is activated, this value defines the timeframe for the activity of the global contacts that are fetched from other servers.'), $poco_discovery_since_choices],
diff --git a/src/Protocol/ActivityPub.php b/src/Protocol/ActivityPub.php
index c22bbb333d..894c7f6d36 100644
--- a/src/Protocol/ActivityPub.php
+++ b/src/Protocol/ActivityPub.php
@@ -231,13 +231,13 @@ class ActivityPub
 			$items = $data['orderedItems'];
 		} elseif (!empty($data['first']['orderedItems'])) {
 			$items = $data['first']['orderedItems'];
-		} elseif (!empty($data['first'])) {
+		} elseif (!empty($data['first']) && is_string($data['first'])) {
 			return self::fetchItems($data['first'], $uid);
 		} else {
 			$items = [];
 		}
 
-		if (!empty($data['next'])) {
+		if (!empty($data['next']) && is_string($data['next'])) {
 			$items = array_merge($items, self::fetchItems($data['next'], $uid));
 		}
 
diff --git a/src/Protocol/ActivityPub/Transmitter.php b/src/Protocol/ActivityPub/Transmitter.php
index ead0c84c0d..f6c9311fcc 100644
--- a/src/Protocol/ActivityPub/Transmitter.php
+++ b/src/Protocol/ActivityPub/Transmitter.php
@@ -345,7 +345,7 @@ class Transmitter
 					continue;
 				}
 
-				if ($receiver == $profile['followers'] && !empty($item_profile['followers'])) {
+				if (!empty($profile['followers']) && $receiver == $profile['followers'] && !empty($item_profile['followers'])) {
 					$permissions[$element][] = $item_profile['followers'];
 				} elseif (!in_array($receiver, $exclude)) {
 					$permissions[$element][] = $receiver;
diff --git a/src/Worker/UpdateGContact.php b/src/Worker/UpdateGContact.php
index 7bdaec464c..0d0d85fc01 100644
--- a/src/Worker/UpdateGContact.php
+++ b/src/Worker/UpdateGContact.php
@@ -22,8 +22,8 @@
 namespace Friendica\Worker;
 
 use Friendica\Core\Logger;
+use Friendica\DI;
 use Friendica\Model\GContact;
-use Friendica\Database\DBA;
 
 class UpdateGContact
 {
@@ -39,5 +39,9 @@ class UpdateGContact
 		$success = GContact::updateFromProbe($url, $force);
 
 		Logger::info('Updated from probe', ['url' => $url, 'force' => $force, 'success' => $success]);
+
+		if ($success && DI::config()->get('system', 'gcontact_discovery')) {
+			GContact::discoverFollowers($url);
+		}
 	}
 }
diff --git a/view/templates/admin/site.tpl b/view/templates/admin/site.tpl
index 9ccda33eeb..9e601b078c 100644
--- a/view/templates/admin/site.tpl
+++ b/view/templates/admin/site.tpl
@@ -98,6 +98,7 @@
 
 	<h3>{{$portable_contacts}}</h3>
 	{{include file="field_checkbox.tpl" field=$poco_completion}}
+	{{include file="field_checkbox.tpl" field=$gcontact_discovery}}
 	{{include file="field_input.tpl" field=$poco_requery_days}}
 	{{include file="field_select.tpl" field=$poco_discovery}}
 	{{include file="field_select.tpl" field=$poco_discovery_since}}
diff --git a/view/theme/frio/templates/admin/site.tpl b/view/theme/frio/templates/admin/site.tpl
index e13b2960e0..e4b05d453d 100644
--- a/view/theme/frio/templates/admin/site.tpl
+++ b/view/theme/frio/templates/admin/site.tpl
@@ -213,6 +213,7 @@
 				<div id="admin-settings-contacts-collapse" class="panel-collapse collapse" role="tabpanel" aria-labelledby="admin-settings-cocontactsrporate">
 
 					{{include file="field_checkbox.tpl" field=$poco_completion}}
+					{{include file="field_checkbox.tpl" field=$gcontact_discovery}}
 					{{include file="field_input.tpl" field=$poco_requery_days}}
 					{{include file="field_select.tpl" field=$poco_discovery}}
 					{{include file="field_select.tpl" field=$poco_discovery_since}}