Static assertion failed error when trying to use std::vector

I have the below class and it's header file. When I include the line std::vector<std::thread> threads; in ProducerManager.h, I get the error shown at the bottom of this question. I have gone through multiple SO questions where the issue was not using std::move() to move the thread into the vector, however, apparently since I am doing it by rvalue it should work. But I get this weird error I don't understand. Could anyone be so kind as to help me out?

// ProducerManager.h

#include <thread>
#include <queue>

#include "Producer.h"

class ProducerManager {
  public:
    ProducerManager(std::queue<std::string> *buffer, Semaphore *items);
    int run();
  private:
    std::queue<std::string> *buffer;
    Semaphore *items;
    bool empty_page_reached = false;
    unsigned int max_threads = 50;
    unsigned int num_pages = 0;
    std::vector<std::thread> threads;   // If I remove this line, I no longer get the error
    std::vector<Producer*> producers;
    std::queue<int> pids;
};

// ProducerManager.cc

#include "ProducerManager.h"

ProducerManager::ProducerManager(std::queue<std::string> *buffer, Semaphore *items) {
  this->buffer = buffer;
  this->items = items;
}

int ProducerManager::run(void) {
  // Create initial threads
  for (unsigned int i = 0; i < max_threads; i++) {
    producers.push_back(new Producer("http://example.com/stuff.json?page="+std::to_string(i+1), i+1, buffer, items, &pids, &empty_page_reached));
    threads.push_back(std::thread(&Producer::perform, producers[i]));
    num_pages++;
  }

  // Keep respawning threads while we haven't yet found an empty page
  while(!empty_page_reached) {
    if (!pids.empty()) {
      // Replace the thread corresponding to a finished page number
      int idx = pids.front() - 1;
      threads[idx].join();
      delete producers[idx];
      producers[idx] = new Producer("http://example.com/stuff.json?page="+std::to_string(num_pages+1), num_pages+1, buffer, items, &pids, &empty_page_reached);
      threads[idx] = std::thread(&Producer::perform, producers[idx]);
      pids.pop();
      num_pages++;
    }
  }

  // Clean up all remaining threads
  while(!pids.empty()) {
    int idx = pids.front() - 1;
    threads[idx].join();
    delete producers[idx];
    pids.pop();
    num_pages++;
  }

  return num_pages;
}

Error:

/usr/include/c++/9.2.1/bits/stl_uninitialized.h: In instantiation of ‘_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = __gnu_cxx::__normal_iterator<const std::thread*, std::vector<std::thread> >; _ForwardIterator = std::thread*]’:
/usr/include/c++/9.2.1/bits/stl_uninitialized.h:307:37:   required from ‘_ForwardIterator std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator, std::allocator<_Tp>&) [with _InputIterator = __gnu_cxx::__normal_iterator<const std::thread*, std::vector<std::thread> >; _ForwardIterator = std::thread*; _Tp = std::thread]’
/usr/include/c++/9.2.1/bits/stl_vector.h:555:31:   required from ‘std::vector<_Tp, _Alloc>::vector(const std::vector<_Tp, _Alloc>&) [with _Tp = std::thread; _Alloc = std::allocator<std::thread>]’ProducerManager.h:6:7:   required from ‘constexpr std::_Head_base<_Idx, _Head, false>::_Head_base(_UHead&&) [with _UHead = ProducerManager&; long unsigned int _Idx = 1; _Head = ProducerManager]’/usr/include/c++/9.2.1/tuple:349:38:   required from ‘static std::thread::_Invoker<std::tuple<typename std::decay<_Tp>::type, typename std::decay<_Args>::type ...> > std::thread::__make_invoker(_Callable&&, _Args&& ...) [with _Callable = int (ProducerManager::*)(); _Args = {ProducerManager&}; typename std::decay<_Tp>::type = int (ProducerManager::*)()]’/usr/include/c++/9.2.1/thread:131:22:   required from ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = int (ProducerManager::*)(); _Args = {ProducerManager&}; <template-parameter-1-3> = void]’main.cc:17:50:   required from here
/usr/include/c++/9.2.1/bits/stl_uninitialized.h:127:72: error: static assertion failed: result type must be constructible from value type of input range  127 |       static_assert(is_constructible<_ValueType2, decltype(*__first)>::value,