diff --git a/bioimageio_collection_backoffice/backup.py b/bioimageio_collection_backoffice/backup.py
index 045a0b6d..02944a94 100644
--- a/bioimageio_collection_backoffice/backup.py
+++ b/bioimageio_collection_backoffice/backup.py
@@ -212,23 +212,24 @@ def rdf_to_metadata(
         # "communities": [],
     }
 
-    # check if license id is valid:
-    license_response = requests.get(
-        f"https://zenodo.org/api/vocabularies/licenses/{rdf.license.lower()}"
-    )
-    try:
-        raise_for_status_discretely(license_response)
-    except Exception as e:
-        logger.error(str(e))
-        logger.error(
-            (
-                f"License '{rdf.license}' not known to Zenodo."
-                + " Please add manually as custom license"
-                + " (as this is currently not supported to do via REST API)"
-            )
+    if rdf.license is not None:
+        # check if license id is valid:
+        license_response = requests.get(
+            f"https://zenodo.org/api/vocabularies/licenses/{rdf.license.lower()}"
         )
-    else:
-        ret["license"] = rdf.license
+        try:
+            raise_for_status_discretely(license_response)
+        except Exception as e:
+            logger.error(str(e))
+            logger.error(
+                (
+                    f"License '{rdf.license}' not known to Zenodo."
+                    + " Please add manually as custom license"
+                    + " (as this is currently not supported to do via REST API)"
+                )
+            )
+        else:
+            ret["license"] = rdf.license
 
     return ret
 
diff --git a/bioimageio_collection_backoffice/collection_config/collection_json_template.py b/bioimageio_collection_backoffice/collection_config/collection_json_template.py
index fe203315..cb1b17ae 100644
--- a/bioimageio_collection_backoffice/collection_config/collection_json_template.py
+++ b/bioimageio_collection_backoffice/collection_config/collection_json_template.py
@@ -4,7 +4,12 @@
 
 from typing import Any, Literal, Optional, Sequence
 
-from bioimageio.spec.generic.v0_3 import Author, CiteEntry, LicenseId, Version
+from bioimageio.spec.generic.v0_3 import (
+    Author,
+    CiteEntry,
+    LicenseId,  # type: ignore
+    Version,
+)
 from pydantic import HttpUrl
 
 from ..common import Node
diff --git a/bioimageio_collection_backoffice/mailroom/_forward_emails_to_chat.py b/bioimageio_collection_backoffice/mailroom/_forward_emails_to_chat.py
index 52db82ca..e2368d5a 100644
--- a/bioimageio_collection_backoffice/mailroom/_forward_emails_to_chat.py
+++ b/bioimageio_collection_backoffice/mailroom/_forward_emails_to_chat.py
@@ -10,7 +10,7 @@
 
 from .._settings import settings
 from ..db_structure.chat import Chat, Message
-from ..remote_collection import get_remote_collection_version
+from ..remote_collection import get_remote_resource_version
 from ..s3_client import Client
 from .constants import (
     BOT_EMAIL,
@@ -93,8 +93,8 @@ def _update_chats(
         text = "[forwarded from email]\n" + body.replace("> " + REPLY_HINT, "").replace(
             REPLY_HINT, ""
         )
-        rr = get_remote_collection_version(s3_client, rid, rv)
-        if not rr.exists:
+        rr = get_remote_resource_version(s3_client, rid, rv)
+        if not rr.exists():
             logger.error("Cannot comment on non-existing resource {} {}", rid, rv)
             continue
 
diff --git a/bioimageio_collection_backoffice/mailroom/send_email.py b/bioimageio_collection_backoffice/mailroom/send_email.py
index 31427b43..4cf7a1fd 100644
--- a/bioimageio_collection_backoffice/mailroom/send_email.py
+++ b/bioimageio_collection_backoffice/mailroom/send_email.py
@@ -1,5 +1,4 @@
 import smtplib
-import sys
 from email.mime.text import MIMEText
 from typing import List, Union
 
diff --git a/tests/test_utils/test_remote_resource.py b/tests/test_utils/test_remote_resource.py
index 561f63cd..7ae38bf0 100644
--- a/tests/test_utils/test_remote_resource.py
+++ b/tests/test_utils/test_remote_resource.py
@@ -1,6 +1,3 @@
-from pathlib import Path
-
-from bioimageio_collection_backoffice._settings import settings
 from bioimageio_collection_backoffice.backup import backup
 from bioimageio_collection_backoffice.remote_collection import (
     Record,
@@ -35,7 +32,7 @@ def test_lifecycle(
 
     remote_collection.generate_collection_json()
 
-    backup(client, settings.zenodo_test_url)
+    backup(client)
 
     assert concept.doi is not None
     assert published.doi is not None