diff --git a/dandi/dandiapi.py b/dandi/dandiapi.py
index 435cd9a55..171a44c06 100644
--- a/dandi/dandiapi.py
+++ b/dandi/dandiapi.py
@@ -248,10 +248,10 @@ def request(
             if isinstance(e, requests.HTTPError):
                 lgr.error(
                     "HTTP request failed repeatedly: Error %d while sending %s request to %s: %s",
-                    e.response.status_code,
+                    e.response.status_code if e.response is not None else "?",
                     method,
                     url,
-                    e.response.text,
+                    e.response.text if e.response is not None else "?",
                 )
             else:
                 lgr.exception("HTTP connection failed")
diff --git a/dandi/dandiarchive.py b/dandi/dandiarchive.py
index 97c86ce5b..ebbd6d96b 100644
--- a/dandi/dandiarchive.py
+++ b/dandi/dandiarchive.py
@@ -165,7 +165,11 @@ def navigate(
             try:
                 dandiset = self.get_dandiset(client, lazy=not strict)
             except requests.HTTPError as e:
-                if e.response.status_code == 401 and authenticate is not False:
+                if (
+                    e.response is not None
+                    and e.response.status_code == 401
+                    and authenticate is not False
+                ):
                     lgr.info("Resource requires authentication; authenticating ...")
                     client.dandi_authenticate()
                     dandiset = self.get_dandiset(client, lazy=not strict)
@@ -293,7 +297,11 @@ def navigate(
             try:
                 assets = list(self.get_assets(client, strict=strict))
             except requests.HTTPError as e:
-                if e.response.status_code == 401 and authenticate is not False:
+                if (
+                    e.response is not None
+                    and e.response.status_code == 401
+                    and authenticate is not False
+                ):
                     lgr.info("Resource requires authentication; authenticating ...")
                     client.dandi_authenticate()
                     assets = list(self.get_assets(client, strict=strict))
diff --git a/dandi/download.py b/dandi/download.py
index 73635da9d..e98c67ab6 100644
--- a/dandi/download.py
+++ b/dandi/download.py
@@ -700,10 +700,14 @@ def _download_file(
         except requests.exceptions.HTTPError as exc:
             # TODO: actually we should probably retry only on selected codes, and also
             # respect Retry-After
-            if attempt >= 2 or exc.response.status_code not in (
-                400,  # Bad Request, but happened with gider:
-                # https://github.com/dandi/dandi-cli/issues/87
-                *RETRY_STATUSES,
+            if attempt >= 2 or (
+                exc.response is not None
+                and exc.response.status_code
+                not in (
+                    400,  # Bad Request, but happened with gider:
+                    # https://github.com/dandi/dandi-cli/issues/87
+                    *RETRY_STATUSES,
+                )
             ):
                 lgr.debug("Download failed: %s", exc)
                 yield {"status": "error", "message": str(exc)}
diff --git a/dandi/files/bases.py b/dandi/files/bases.py
index 83e4f01f1..b8cfe38b1 100644
--- a/dandi/files/bases.py
+++ b/dandi/files/bases.py
@@ -362,7 +362,7 @@ def iter_upload(
                 },
             )
         except requests.HTTPError as e:
-            if e.response.status_code == 409:
+            if e.response is not None and e.response.status_code == 409:
                 lgr.debug("%s: Blob already exists on server", asset_path)
                 blob_id = e.response.headers["Location"]
             else:
diff --git a/dandi/files/zarr.py b/dandi/files/zarr.py
index 1a06dd553..34199793d 100644
--- a/dandi/files/zarr.py
+++ b/dandi/files/zarr.py
@@ -299,7 +299,7 @@ def mkzarr() -> str:
                     json={"name": asset_path, "dandiset": dandiset.identifier},
                 )
             except requests.HTTPError as e:
-                if "Zarr already exists" in e.response.text:
+                if e.response is not None and "Zarr already exists" in e.response.text:
                     lgr.warning(
                         "%s: Found pre-existing Zarr at same path not"
                         " associated with any asset; reusing",