SFTP connection failing when shouldn't be tested
 ## Reproduce
1. Enable `Site Sync` module, create a `SFTP` site with wrong credentials and enable it for your production.
2. Change your local settings to `local` and `studio` (not to the `sftp` site).
3. Restart Tray, and look to the logs, it tries to connect when it shouldn't because the user settings don't ask for it.

The logs produced make bug hunting more tedious and slows the server to start because of attempts to connect.

## Lead
This is caused by `is_active` in `openpype\\modules\\sync_server\\providers\\sftp.py` which tries to get the connection to test if the sftp is available.

## Proposals
- Add a check of the current user settings, if the sftp site is not selected as remote, then `is_active` returns `False`.
- Don't even register the module if the sftp site is not selected as remote.

[cuID:OP-4490]
diff --git a/openpype/modules/sync_server/providers/dropbox.py b/openpype/modules/sync_server/providers/dropbox.py
index 3515aee93f..a517e7d847 100644
--- a/openpype/modules/sync_server/providers/dropbox.py
+++ b/openpype/modules/sync_server/providers/dropbox.py
@@ -165,7 +165,7 @@ class DropboxHandler(AbstractProvider):
         Returns:
             (boolean)
         """
-        return self.presets["enabled"] and self.dbx is not None
+        return self.presets.get("enabled") and self.dbx is not None
 
     @classmethod
     def get_configurable_items(cls):
diff --git a/openpype/modules/sync_server/providers/gdrive.py b/openpype/modules/sync_server/providers/gdrive.py
index 297a5c9fec..4e24fe41d2 100644
--- a/openpype/modules/sync_server/providers/gdrive.py
+++ b/openpype/modules/sync_server/providers/gdrive.py
@@ -119,7 +119,7 @@ class GDriveHandler(AbstractProvider):
         Returns:
             (boolean)
         """
-        return self.presets["enabled"] and self.service is not None
+        return self.presets.get("enabled") and self.service is not None
 
     @classmethod
     def get_system_settings_schema(cls):
diff --git a/openpype/modules/sync_server/sync_server.py b/openpype/modules/sync_server/sync_server.py
index d0a40a60ff..85b0774e90 100644
--- a/openpype/modules/sync_server/sync_server.py
+++ b/openpype/modules/sync_server/sync_server.py
@@ -169,7 +169,7 @@ def resolve_paths(module, file_path, project_name,
     return local_file_path, remote_file_path
 
 
-def site_is_working(module, project_name, site_name):
+def _site_is_working(module, project_name, site_name, site_config):
     """
         Confirm that 'site_name' is configured correctly for 'project_name'.
 
@@ -179,54 +179,17 @@ def site_is_working(module, project_name, site_name):
             module (SyncServerModule)
             project_name(string):
             site_name(string):
+            site_config (dict): configuration for site from Settings
         Returns
             (bool)
     """
-    if _get_configured_sites(module, project_name).get(site_name):
-        return True
-    return False
+    provider = module.get_provider_for_site(site=site_name)
+    handler = lib.factory.get_provider(provider,
+                                       project_name,
+                                       site_name,
+                                       presets=site_config)
 
-
-def _get_configured_sites(module, project_name):
-    """
-        Loops through settings and looks for configured sites and checks
-        its handlers for particular 'project_name'.
-
-        Args:
-            project_setting(dict): dictionary from Settings
-            only_project_name(string, optional): only interested in
-                particular project
-        Returns:
-            (dict of dict)
-            {'ProjectA': {'studio':True, 'gdrive':False}}
-    """
-    settings = module.get_sync_project_setting(project_name)
-    return _get_configured_sites_from_setting(module, project_name, settings)
-
-
-def _get_configured_sites_from_setting(module, project_name, project_setting):
-    if not project_setting.get("enabled"):
-        return {}
-
-    initiated_handlers = {}
-    configured_sites = {}
-    all_sites = module._get_default_site_configs()
-    all_sites.update(project_setting.get("sites"))
-    for site_name, config in all_sites.items():
-        provider = module.get_provider_for_site(site=site_name)
-        handler = initiated_handlers.get((provider, site_name))
-        if not handler:
-            handler = lib.factory.get_provider(provider,
-                                               project_name,
-                                               site_name,
-                                               presets=config)
-            initiated_handlers[(provider, site_name)] = \\
-                handler
-
-        if handler.is_active():
-            configured_sites[site_name] = True
-
-    return configured_sites
+    return handler.is_active()
 
 
 class SyncServerThread(threading.Thread):
@@ -288,7 +251,8 @@ class SyncServerThread(threading.Thread):
                 for project_name in enabled_projects:
                     preset = self.module.sync_project_settings[project_name]
 
-                    local_site, remote_site = self._working_sites(project_name)
+                    local_site, remote_site = self._working_sites(project_name,
+                                                                  preset)
                     if not all([local_site, remote_site]):
                         continue
 
@@ -464,7 +428,7 @@ class SyncServerThread(threading.Thread):
             self.timer.cancel()
             self.timer = None
 
-    def _working_sites(self, project_name):
+    def _working_sites(self, project_name, sync_config):
         if self.module.is_project_paused(project_name):
             self.log.debug("Both sites same, skipping")
             return None, None
@@ -476,9 +440,12 @@ class SyncServerThread(threading.Thread):
                 local_site, remote_site))
             return None, None
 
-        configured_sites = _get_configured_sites(self.module, project_name)
-        if not all([local_site in configured_sites,
-                    remote_site in configured_sites]):
+        local_site_config = sync_config.get('sites')[local_site]
+        remote_site_config = sync_config.get('sites')[remote_site]
+        if not all([_site_is_working(self.module, project_name, local_site,
+                                     local_site_config),
+                    _site_is_working(self.module, project_name, remote_site,
+                                     remote_site_config)]):
             self.log.debug(
                 "Some of the sites {} - {} is not working properly".format(
                     local_site, remote_site
['openpype/modules/sync_server/providers/gdrive.py', 'openpype/modules/sync_server/providers/dropbox.py', 'openpype/modules/sync_server/sync_server.py']