diff --git a/app/lib/activitypub/activity/create.rb b/app/lib/activitypub/activity/create.rb
index 5d700b49613..95163c6111d 100644
--- a/app/lib/activitypub/activity/create.rb
+++ b/app/lib/activitypub/activity/create.rb
@@ -225,7 +225,11 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     return if tag['href'].blank?
 
     account = account_from_uri(tag['href'])
-    account = ActivityPub::FetchRemoteAccountService.new.call(tag['href'], request_id: @options[:request_id]) if account.nil?
+    begin
+      account = ActivityPub::FetchRemoteAccountService.new.call(tag['href'], request_id: @options[:request_id]) if account.nil?
+    rescue Mastodon::UnexpectedResponseError, HTTP::TimeoutError, HTTP::ConnectionError, OpenSSL::SSL::SSLError
+      account = nil
+    end
 
     return if account.nil?
 
diff --git a/spec/lib/activitypub/activity/create_spec.rb b/spec/lib/activitypub/activity/create_spec.rb
index dec17b916b8..f7c8d7ee9b0 100644
--- a/spec/lib/activitypub/activity/create_spec.rb
+++ b/spec/lib/activitypub/activity/create_spec.rb
@@ -63,6 +63,24 @@ RSpec.describe ActivityPub::Activity::Create do
       }
     end
 
+    let(:invalid_mention_json) do
+      {
+        id: [ActivityPub::TagManager.instance.uri_for(sender), 'post2'].join('/'),
+        type: 'Note',
+        to: [
+          'https://www.w3.org/ns/activitystreams#Public',
+          ActivityPub::TagManager.instance.uri_for(follower),
+        ],
+        content: '@bob lorem ipsum',
+        published: 1.hour.ago.utc.iso8601,
+        updated: 1.hour.ago.utc.iso8601,
+        tag: {
+          type: 'Mention',
+          href: 'http://notexisting.dontexistingtld/actor',
+        },
+      }
+    end
+
     def activity_for_object(json)
       {
         '@context': 'https://www.w3.org/ns/activitystreams',
@@ -117,6 +135,22 @@ RSpec.describe ActivityPub::Activity::Create do
       # Creates two notifications
       expect(Notification.count).to eq 2
     end
+
+    it 'ignores unprocessable mention', :aggregate_failures do
+      stub_request(:get, invalid_mention_json[:tag][:href]).to_raise(HTTP::ConnectionError)
+      # When receiving the post that contains an invalid mention…
+      described_class.new(activity_for_object(invalid_mention_json), sender, delivery: true).perform
+
+      # NOTE: Refering explicitly to the workers is a bit awkward
+      DistributionWorker.drain
+      FeedInsertWorker.drain
+
+      # …it creates a status with an unknown parent
+      status = Status.find_by(uri: invalid_mention_json[:id])
+
+      # Check the process did not crash
+      expect(status.nil?).to be false
+    end
   end
 
   describe '#perform' do