エラーが発生しました

array (
  'type' => 1,
  'message' => 'Uncaught TypeError: Argument 2 passed to ButtonSocialUtil::_convertTitle() must be of the type string, null given, called in /virtual/plaza/public_html/bunko.jp/set/common/site_include/plugin/ButtonSocial/util/ButtonSocialUtil.class.php on line 42 and defined in /virtual/plaza/public_html/bunko.jp/set/common/site_include/plugin/ButtonSocial/util/ButtonSocialUtil.class.php:46
Stack trace:
#0 /virtual/plaza/public_html/bunko.jp/set/common/site_include/plugin/ButtonSocial/util/ButtonSocialUtil.class.php(42): ButtonSocialUtil::_convertTitle()
#1 /virtual/plaza/public_html/bunko.jp/set/common/site_include/plugin/ButtonSocial/logic/BuildMetaLogic.class.php(20): ButtonSocialUtil::getTitle()
#2 /virtual/plaza/public_html/bunko.jp/set/common/site_include/plugin/ButtonSocial/ButtonSocial.php(138): BuildMetaLogic->buildOgMeta()
#3 /virtual/plaza/public_html/bunko.jp/set/common/util/CMSPlugin.class.php(420): ButtonSocialPlugin->onPageOutput()
#4 /virtual/plaza/public_html/bunko.jp/set/common/site_include/CMSPage.class.ph',
  'file' => '/virtual/plaza/public_html/bunko.jp/set/common/site_include/plugin/ButtonSocial/util/ButtonSocialUtil.class.php',
  'line' => 46,
)