大约 7-10 天前，Discourse 停止从我们的 WordPress 安装创建任何新主题。WP 使用的是 wp-discourse-embed，因此是通过 iFrame/JavaScript 嵌入评论。据我们所知，配置方面没有任何变化。我们得到的唯一线索是 Discourse 错误日志中现在出现了一大堆类似以下的错误：
作业异常：undefined method `+@’ for #Nokogiri::XML::Element:0x00007f3ad52d6ba0
回溯：
/var/www/discourse/app/models/topic_embed.rb:40:in `import'
/var/www/discourse/app/models/topic_embed.rb:186:in `import_remote'
/var/www/discourse/lib/topic_retriever.rb:58:in `fetch_http'
/var/www/discourse/lib/topic_retriever.rb:45:in `perform_retrieve'
/var/www/discourse/lib/topic_retriever.rb:12:in `retrieve'
/var/www/discourse/app/jobs/regular/retrieve_topic.rb:18:in `execute'
/var/www/discourse/app/jobs/base.rb:232:in `block (2 levels) in perform'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/rails_multisite-2.0.7/lib/rails_multisite/connection_management.rb:63:in `with_connection'
/var/www/discourse/app/jobs/base.rb:221:in `block in perform'
/var/www/discourse/app/jobs/base.rb:217:in `each'
/var/www/discourse/app/jobs/base.rb:217:in `perform'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:192:in `execute_job'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:165:in `block (2 levels) in process'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/middleware/chain.rb:128:in `block in invoke'
/var/www/discourse/lib/sidekiq/pausable.rb:138:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/middleware/chain.rb:130:in `block in invoke'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/middleware/chain.rb:133:in `invoke'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:164:in `block in process'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:137:in `block (6 levels) in dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/job_retry.rb:109:in `local'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:136:in `block (5 levels) in dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq.rb:37:in `block in <module:Sidekiq>'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:132:in `block (4 levels) in dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:250:in `stats'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:127:in `block (3 levels) in dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/job_logger.rb:8:in `call'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:126:in `block (2 levels) in dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/job_retry.rb:74:in `global'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:125:in `block in dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/logging.rb:48:in `with_context'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/logging.rb:42:in `with_job_hash_context'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:124:in `dispatch'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:163:in `process'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:83:in `process_one'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/processor.rb:71:in `run'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/util.rb:16:in `watchdog'
/var/www/discourse/vendor/bundle/ruby/2.6.0/gems/sidekiq-5.2.7/lib/sidekiq/util.rb:25:in `block in safe_thread'
环境：
hostname forum-app
process_id 26059
application_version 4b9d35cd0e6d2050f8103f9b5314fe43000f5e42
current_db default
current_hostname forum.quartertothree.com
job Jobs::RetrieveTopic
problem_db default
opts null
user_id 20008
embed_url https://www.quartertothree.com/fp/2019/08/05/the-migration-to-mixer-faces-some-clothing-challenges/
referer https://www.quartertothree.com/fp/2019/08/05/the-migration-to-mixer-faces-some-clothing-challenges/
current_site_id default
有人能提供任何想法/建议/祈祷吗？
谢谢。