diff --git a/blog.py b/blog.py
index 2101c8e3..e41aacdf 100644
--- a/blog.py
+++ b/blog.py
@@ -170,8 +170,10 @@ def htmlBlogPostContent(authorized: bool,
 
     # get the handle of the author
     if postJsonObject['object'].get('attributedTo'):
-        actor = postJsonObject['object']['attributedTo']
-        authorNickname = getNicknameFromActor(actor)
+        authorNickname = None
+        if isinstance(postJsonObject['object']['attributedTo'], str):
+            actor = postJsonObject['object']['attributedTo']
+            authorNickname = getNicknameFromActor(actor)
         if authorNickname:
             authorDomain, authorPort = getDomainFromActor(actor)
             if authorDomain:
diff --git a/git.py b/git.py
index ffe8e131..68680e33 100644
--- a/git.py
+++ b/git.py
@@ -126,6 +126,8 @@ def convertPostToPatch(baseDir: str, nickname: str, domain: str,
         return False
     if not postJsonObject['object'].get('attributedTo'):
         return False
+    if not isinstance(postJsonObject['object']['attributedTo'], str):
+        return False
     if not isGitPatch(baseDir, nickname, domain,
                       postJsonObject['object']['type'],
                       postJsonObject['object']['summary'],
diff --git a/inbox.py b/inbox.py
index 2a9dfae1..15bf74a2 100644
--- a/inbox.py
+++ b/inbox.py
@@ -1422,12 +1422,15 @@ def receiveAnnounce(recentPostsCache: {},
         # so that their avatar can be shown
         lookupActor = None
         if postJsonObject.get('attributedTo'):
-            lookupActor = postJsonObject['attributedTo']
+            if isinstance(postJsonObject['attributedTo'], str):
+                lookupActor = postJsonObject['attributedTo']
         else:
             if postJsonObject.get('object'):
                 if isinstance(postJsonObject['object'], dict):
                     if postJsonObject['object'].get('attributedTo'):
-                        lookupActor = postJsonObject['object']['attributedTo']
+                        attrib = postJsonObject['object']['attributedTo']
+                        if isinstance(attrib, str):
+                            lookupActor = attrib
         if lookupActor:
             if '/users/' in lookupActor or \
                '/channel/' in lookupActor or \
@@ -2190,24 +2193,25 @@ def inboxAfterCapabilities(recentPostsCache: {}, maxRecentPosts: int,
                postJsonObject['object'].get('summary') and \
                postJsonObject['object'].get('attributedTo'):
                 attributedTo = postJsonObject['object']['attributedTo']
-                fromNickname = getNicknameFromActor(attributedTo)
-                fromDomain, fromPort = getDomainFromActor(attributedTo)
-                if fromPort:
-                    if fromPort != 80 and fromPort != 443:
-                        fromDomain += ':' + str(fromPort)
-                if receiveGitPatch(baseDir, nickname, domain,
-                                   postJsonObject['object']['type'],
-                                   postJsonObject['object']['summary'],
-                                   postJsonObject['object']['content'],
-                                   fromNickname, fromDomain):
-                    gitPatchNotify(baseDir, handle,
-                                   postJsonObject['object']['summary'],
-                                   postJsonObject['object']['content'],
-                                   fromNickname, fromDomain)
-                elif '[PATCH]' in postJsonObject['object']['content']:
-                    print('WARN: git patch not accepted - ' +
-                          postJsonObject['object']['summary'])
-                    return False
+                if isinstance(attributedTo, str):
+                    fromNickname = getNicknameFromActor(attributedTo)
+                    fromDomain, fromPort = getDomainFromActor(attributedTo)
+                    if fromPort:
+                        if fromPort != 80 and fromPort != 443:
+                            fromDomain += ':' + str(fromPort)
+                    if receiveGitPatch(baseDir, nickname, domain,
+                                       postJsonObject['object']['type'],
+                                       postJsonObject['object']['summary'],
+                                       postJsonObject['object']['content'],
+                                       fromNickname, fromDomain):
+                        gitPatchNotify(baseDir, handle,
+                                       postJsonObject['object']['summary'],
+                                       postJsonObject['object']['content'],
+                                       fromNickname, fromDomain)
+                    elif '[PATCH]' in postJsonObject['object']['content']:
+                        print('WARN: git patch not accepted - ' +
+                              postJsonObject['object']['summary'])
+                        return False
 
         # replace YouTube links, so they get less tracking data
         replaceYouTube(postJsonObject, YTReplacementDomain)
diff --git a/webinterface.py b/webinterface.py
index 4ebf561b..fbb1d826 100644
--- a/webinterface.py
+++ b/webinterface.py
@@ -3813,8 +3813,9 @@ def individualPostAsHtml(recentPostsCache: {}, maxRecentPosts: int,
     if showIcons:
         replyToLink = postJsonObject['object']['id']
         if postJsonObject['object'].get('attributedTo'):
-            replyToLink += \
-                '?mention=' + postJsonObject['object']['attributedTo']
+            if isinstance(postJsonObject['object']['attributedTo'], str):
+                replyToLink += \
+                    '?mention=' + postJsonObject['object']['attributedTo']
         if postJsonObject['object'].get('content'):
             mentionedActors = \
                 getMentionsFromHtml(postJsonObject['object']['content'])
@@ -3985,7 +3986,9 @@ def individualPostAsHtml(recentPostsCache: {}, maxRecentPosts: int,
     if showRepeatIcon:
         if isAnnounced:
             if postJsonObject['object'].get('attributedTo'):
-                attributedTo = postJsonObject['object']['attributedTo']
+                attributedTo = ''
+                if isinstance(postJsonObject['object']['attributedTo'], str):
+                    attributedTo = postJsonObject['object']['attributedTo']
                 if attributedTo.startswith(postActor):
                     titleStr += \
                         ' <img loading="lazy" title="' + \
@@ -3994,8 +3997,9 @@ def individualPostAsHtml(recentPostsCache: {}, maxRecentPosts: int,
                         '" src="/' + iconsDir + \
                         '/repeat_inactive.png" class="announceOrReply"/>\n'
                 else:
-                    announceNickname = \
-                        getNicknameFromActor(attributedTo)
+                    announceNickname = None
+                    if attributedTo:
+                        announceNickname = getNicknameFromActor(attributedTo)
                     if announceNickname:
                         announceDomain, announcePort = \
                             getDomainFromActor(attributedTo)