diff --git a/youtube_dl/extractor/common.py b/youtube_dl/extractor/common.py
index 859786617..50d48c40d 100644
--- a/youtube_dl/extractor/common.py
+++ b/youtube_dl/extractor/common.py
@@ -1424,12 +1424,10 @@ class InfoExtractor(object):
         try:
             self._request_webpage(url, video_id, 'Checking %s URL' % item, headers=headers)
             return True
-        except ExtractorError as e:
-            if isinstance(e.cause, compat_urllib_error.URLError):
-                self.to_screen(
-                    '%s: %s URL is invalid, skipping' % (video_id, item))
-                return False
-            raise
+        except ExtractorError:
+            self.to_screen(
+                '%s: %s URL is invalid, skipping' % (video_id, item))
+            return False
 
     def http_scheme(self):
         """ Either "http:" or "https:", depending on the user's preferences """
diff --git a/youtube_dl/extractor/orf.py b/youtube_dl/extractor/orf.py
index 499be0029..3425f7602 100644
--- a/youtube_dl/extractor/orf.py
+++ b/youtube_dl/extractor/orf.py
@@ -86,12 +86,13 @@ class ORFTVthekIE(InfoExtractor):
                     if value:
                         format_id_list.append(value)
                 format_id = '-'.join(format_id_list)
-                if determine_ext(fd['src']) == 'm3u8':
+                ext = determine_ext(src)
+                if ext == 'm3u8':
                     formats.extend(self._extract_m3u8_formats(
-                        fd['src'], video_id, 'mp4', m3u8_id=format_id))
-                elif determine_ext(fd['src']) == 'f4m':
+                        src, video_id, 'mp4', m3u8_id=format_id, fatal=False))
+                elif ext == 'f4m':
                     formats.extend(self._extract_f4m_formats(
-                        fd['src'], video_id, f4m_id=format_id))
+                        src, video_id, f4m_id=format_id, fatal=False))
                 else:
                     formats.append({
                         'format_id': format_id,
diff --git a/youtube_dl/extractor/teachable.py b/youtube_dl/extractor/teachable.py
index c1a9deafe..7d2e34b3b 100644
--- a/youtube_dl/extractor/teachable.py
+++ b/youtube_dl/extractor/teachable.py
@@ -48,6 +48,16 @@ class TeachableBaseIE(InfoExtractor):
             'https://%s/sign_in' % site, None,
             'Downloading %s login page' % site)
 
+        def is_logged(webpage):
+            return any(re.search(p, webpage) for p in (
+                r'class=["\']user-signout',
+                r'<a[^>]+\bhref=["\']/sign_out',
+                r'Log\s+[Oo]ut\s*<'))
+
+        if is_logged(login_page):
+            self._logged_in = True
+            return
+
         login_url = compat_str(urlh.geturl())
 
         login_form = self._hidden_inputs(login_page)
@@ -78,10 +88,7 @@ class TeachableBaseIE(InfoExtractor):
                 'Go to https://%s/ and accept.' % (site, site), expected=True)
 
         # Successful login
-        if any(re.search(p, response) for p in (
-                r'class=["\']user-signout',
-                r'<a[^>]+\bhref=["\']/sign_out',
-                r'>\s*Log out\s*<')):
+        if is_logged(response):
             self._logged_in = True
             return
 
diff --git a/youtube_dl/extractor/viewlift.py b/youtube_dl/extractor/viewlift.py
index 391419d9e..851ad936c 100644
--- a/youtube_dl/extractor/viewlift.py
+++ b/youtube_dl/extractor/viewlift.py
@@ -179,6 +179,10 @@ class ViewLiftIE(ViewLiftBaseIE):
         'only_matching': True,
     }]
 
+    @classmethod
+    def suitable(cls, url):
+        return False if ViewLiftEmbedIE.suitable(url) else super(ViewLiftIE, cls).suitable(url)
+
     def _real_extract(self, url):
         domain, display_id = re.match(self._VALID_URL, url).groups()