I don't know if this is a problem with ThemeHouse Reactions addon (https://www.themehouse.com/xenforo/2/addons/reactions) or DragonByte User Tagging addon (https://www.dragonbyte-tech.com/store/dragonbyte-user-tagging.378/)
I posted a support thread at ThemeHouse aswell.
Here is the error I get in admincp...
Error: Call to undefined method ThemeHouse\Reactions\XF\Str\Formatter::getHashTagFormatter() src/addons/DBTech/UserTagging/BbCode/ProcessorAction/HashTags.php:54
Generated by: Rick7C2 Aug 9, 2018 at 7:59 PM
Stack trace
#0 [internal function]: DBTech\UserTagging\BbCode\ProcessorAction\HashTags->filterFinal('test', Object(XF\BbCode\Processor))
#1 src/XF/BbCode/Processor.php(192): call_user_func(Array, 'test', Object(XF\BbCode\Processor))
#2 src/XF/BbCode/Traverser.php(30): XF\BbCode\Processor->filterFinalOutput('test')
#3 src/XF/BbCode/Traverser.php(18): XF\BbCode\Traverser->renderAst(Array, Object(KL\EditorManager\XF\BbCode\RuleSet), Array)
#4 src/XF/Service/Message/Preparer.php(154): XF\BbCode\Traverser->render('test', Object(XF\BbCode\Parser), Object(KL\EditorManager\XF\BbCode\RuleSet), Array)
#5 src/XF/Service/Message/Preparer.php(117): XF\Service\Message\Preparer->processMessage('test')
#6 src/addons/DBTech/UserTagging/XF/Service/Message/Preparer.php(37): XF\Service\Message\Preparer->prepare('test', true)
#7 src/XF/Service/Post/Preparer.php(98): DBTech\UserTagging\XF\Service\Message\Preparer->prepare('test', true)
#8 src/addons/DBTech/UserTagging/XF/Service/Post/Preparer.php(45): XF\Service\Post\Preparer->setMessage('test', true, true)
#9 src/XF/Service/Thread/Replier.php(101): DBTech\UserTagging\XF\Service\Post\Preparer->setMessage('test', true, true)
#10 src/XF/Pub/Controller/Thread.php(288): XF\Service\Thread\Replier->setMessage('test')
#11 src/XF/Pub/Controller/Thread.php(423): XF\Pub\Controller\Thread->setupThreadReply(Object(ThemeHouse\Reactions\XF\Entity\Thread))
#12 src/addons/Snog/TV/XF/Pub/Controller/Thread.php(34): XF\Pub\Controller\Thread->actionAddReply(Object(XF\Mvc\ParameterBag))
#13 src/XF/Mvc/Dispatcher.php(249): Snog\TV\XF\Pub\Controller\Thread->actionAddReply(Object(XF\Mvc\ParameterBag))
#14 src/XF/Mvc/Dispatcher.php(88): XF\Mvc\Dispatcher->dispatchClass('XF:Thread', 'AddReply', 'json', Object(XF\Mvc\ParameterBag), 'forums', Object(Siropu\AdsManager\XF\Pub\Controller\Thread), NULL)
#15 src/XF/Mvc/Dispatcher.php(41): XF\Mvc\Dispatcher->dispatchLoop(Object(XF\Mvc\RouteMatch))
#16 src/XF/App.php(1931): XF\Mvc\Dispatcher->run()
#17 src/XF.php(328): XF\App->run()
#18 index.php(13): XF::runApp('XF\\Pub\\App')
#19 {main}
I posted a support thread at ThemeHouse aswell.
Here is the error I get in admincp...
Error: Call to undefined method ThemeHouse\Reactions\XF\Str\Formatter::getHashTagFormatter() src/addons/DBTech/UserTagging/BbCode/ProcessorAction/HashTags.php:54
Generated by: Rick7C2 Aug 9, 2018 at 7:59 PM
Stack trace
#0 [internal function]: DBTech\UserTagging\BbCode\ProcessorAction\HashTags->filterFinal('test', Object(XF\BbCode\Processor))
#1 src/XF/BbCode/Processor.php(192): call_user_func(Array, 'test', Object(XF\BbCode\Processor))
#2 src/XF/BbCode/Traverser.php(30): XF\BbCode\Processor->filterFinalOutput('test')
#3 src/XF/BbCode/Traverser.php(18): XF\BbCode\Traverser->renderAst(Array, Object(KL\EditorManager\XF\BbCode\RuleSet), Array)
#4 src/XF/Service/Message/Preparer.php(154): XF\BbCode\Traverser->render('test', Object(XF\BbCode\Parser), Object(KL\EditorManager\XF\BbCode\RuleSet), Array)
#5 src/XF/Service/Message/Preparer.php(117): XF\Service\Message\Preparer->processMessage('test')
#6 src/addons/DBTech/UserTagging/XF/Service/Message/Preparer.php(37): XF\Service\Message\Preparer->prepare('test', true)
#7 src/XF/Service/Post/Preparer.php(98): DBTech\UserTagging\XF\Service\Message\Preparer->prepare('test', true)
#8 src/addons/DBTech/UserTagging/XF/Service/Post/Preparer.php(45): XF\Service\Post\Preparer->setMessage('test', true, true)
#9 src/XF/Service/Thread/Replier.php(101): DBTech\UserTagging\XF\Service\Post\Preparer->setMessage('test', true, true)
#10 src/XF/Pub/Controller/Thread.php(288): XF\Service\Thread\Replier->setMessage('test')
#11 src/XF/Pub/Controller/Thread.php(423): XF\Pub\Controller\Thread->setupThreadReply(Object(ThemeHouse\Reactions\XF\Entity\Thread))
#12 src/addons/Snog/TV/XF/Pub/Controller/Thread.php(34): XF\Pub\Controller\Thread->actionAddReply(Object(XF\Mvc\ParameterBag))
#13 src/XF/Mvc/Dispatcher.php(249): Snog\TV\XF\Pub\Controller\Thread->actionAddReply(Object(XF\Mvc\ParameterBag))
#14 src/XF/Mvc/Dispatcher.php(88): XF\Mvc\Dispatcher->dispatchClass('XF:Thread', 'AddReply', 'json', Object(XF\Mvc\ParameterBag), 'forums', Object(Siropu\AdsManager\XF\Pub\Controller\Thread), NULL)
#15 src/XF/Mvc/Dispatcher.php(41): XF\Mvc\Dispatcher->dispatchLoop(Object(XF\Mvc\RouteMatch))
#16 src/XF/App.php(1931): XF\Mvc\Dispatcher->run()
#17 src/XF.php(328): XF\App->run()
#18 index.php(13): XF::runApp('XF\\Pub\\App')
#19 {main}