diff --git a/src/DIRAC/FrameworkSystem/Service/ProxyManagerHandler.py b/src/DIRAC/FrameworkSystem/Service/ProxyManagerHandler.py
index 1935514568d..035760ea531 100644
--- a/src/DIRAC/FrameworkSystem/Service/ProxyManagerHandler.py
+++ b/src/DIRAC/FrameworkSystem/Service/ProxyManagerHandler.py
@@ -1,11 +1,12 @@
-""" ProxyManager is the implementation of the ProxyManagement service in the DISET framework
+"""ProxyManager is the implementation of the ProxyManagement service in the DISET framework
 
-    .. literalinclude:: ../ConfigTemplate.cfg
-      :start-after: ##BEGIN ProxyManager:
-      :end-before: ##END
-      :dedent: 2
-      :caption: ProxyManager options
+.. literalinclude:: ../ConfigTemplate.cfg
+  :start-after: ##BEGIN ProxyManager:
+  :end-before: ##END
+  :dedent: 2
+  :caption: ProxyManager options
 """
+
 from DIRAC import S_ERROR, S_OK, gLogger
 from DIRAC.ConfigurationSystem.Client.Helpers import Registry
 from DIRAC.Core.DISET.RequestHandler import RequestHandler, getServiceOption
@@ -325,6 +326,7 @@ def export_exchangeProxyForToken(self):
             credDict["group"],
             set(credDict.get("groupProperties", []) + credDict.get("properties", [])),
             expires_minutes=credDict["secondsLeft"] // 60 + 1,
+            source="ProxyManager",
         )
 
 
diff --git a/src/DIRAC/FrameworkSystem/Utilities/diracx.py b/src/DIRAC/FrameworkSystem/Utilities/diracx.py
index bd97ac23d1a..00818477759 100644
--- a/src/DIRAC/FrameworkSystem/Utilities/diracx.py
+++ b/src/DIRAC/FrameworkSystem/Utilities/diracx.py
@@ -26,8 +26,12 @@
 DEFAULT_TOKEN_CACHE_SIZE = 1024
 
 
-def get_token(username: str, group: str, dirac_properties: set[str], *, expires_minutes: int | None = None):
-    """Do a legacy exchange to get a DiracX access_token+refresh_token"""
+def get_token(
+    username: str, group: str, dirac_properties: set[str], *, expires_minutes: int | None = None, source: str = ""
+):
+    """Do a legacy exchange to get a DiracX access_token+refresh_token
+
+    The source parameter only purpose is to appear in the URL on diracx logs"""
     diracxUrl = gConfig.getValue("/DiracX/URL")
     if not diracxUrl:
         raise ValueError("Missing mandatory /DiracX/URL configuration")
@@ -44,6 +48,7 @@ def get_token(username: str, group: str, dirac_properties: set[str], *, expires_
             "preferred_username": username,
             "scope": " ".join(scopes),
             "expires_minutes": expires_minutes,
+            "source": source,
         },
         headers={"Authorization": f"Bearer {apiKey}"},
         timeout=10,
@@ -58,15 +63,15 @@ def get_token(username: str, group: str, dirac_properties: set[str], *, expires_
     TTLCache(maxsize=DEFAULT_TOKEN_CACHE_SIZE, ttl=DEFAULT_TOKEN_CACHE_TTL),
     key=lambda a, b, c: hashkey(a, b, *sorted(c)),
 )
-def _get_token_file(username: str, group: str, dirac_properties: set[str]) -> Path:
+def _get_token_file(username: str, group: str, dirac_properties: set[str], *, source: str = "") -> Path:
     """Write token to a temporary file and return the path to that file"""
-    data = get_token(username, group, dirac_properties)
+    data = get_token(username, group, dirac_properties, source=source)
     token_location = Path(NamedTemporaryFile().name)
     write_credentials(TokenResponse(**data), location=token_location)
     return token_location
 
 
-def TheImpersonator(credDict: dict[str, Any]) -> SyncDiracClient:
+def TheImpersonator(credDict: dict[str, Any], *, source: str = "") -> SyncDiracClient:
     """
     Client to be used by DIRAC server needing to impersonate
     a user for diracx.
@@ -83,6 +88,7 @@ def TheImpersonator(credDict: dict[str, Any]) -> SyncDiracClient:
         credDict["username"],
         credDict["group"],
         set(credDict.get("groupProperties", []) + credDict.get("properties", [])),
+        source=source,
     )
     pref = DiracxPreferences(url=diracxUrl, credentials_path=token_location)
 
diff --git a/src/DIRAC/WorkloadManagementSystem/Service/SandboxStoreHandler.py b/src/DIRAC/WorkloadManagementSystem/Service/SandboxStoreHandler.py
index cf5075ebfc8..2b361a65470 100755
--- a/src/DIRAC/WorkloadManagementSystem/Service/SandboxStoreHandler.py
+++ b/src/DIRAC/WorkloadManagementSystem/Service/SandboxStoreHandler.py
@@ -120,7 +120,7 @@ def _getFromClient(self, fileId, token, fileSize, fileHelper=None, data=""):
                     format=extension,
                 )
 
-                with TheImpersonator(credDict) as client:
+                with TheImpersonator(credDict, source="SandboxStore") as client:
                     res = client.jobs.initiate_sandbox_upload(sandbox_info)
 
                 if res.url:
@@ -415,7 +415,7 @@ def _sendToClient(self, fileID, token, fileHelper=None, raw=False):
         # If the PFN starts with S3, we know it has been uploaded to the
         # S3 sandbox store, so download it from there before sending it
         if filePath.startswith("/S3"):
-            with TheImpersonator(credDict) as client:
+            with TheImpersonator(credDict, source="SandboxStore") as client:
                 res = client.jobs.get_sandbox_file(pfn=filePath)
                 r = requests.get(res.url)
                 r.raise_for_status()
diff --git a/tests/CI/docker-compose.yml b/tests/CI/docker-compose.yml
index 7942b3289cd..a1fbfe07a14 100644
--- a/tests/CI/docker-compose.yml
+++ b/tests/CI/docker-compose.yml
@@ -83,7 +83,9 @@ services:
 
   # Mock of an S3 storage
   s3-direct:
-    image: adobe/s3mock
+    # Fix the version until https://github.com/adobe/S3Mock/issues/2321
+    # is resolved
+    image: adobe/s3mock:3.12.0
     container_name: s3-direct
     hostname: s3-direct
     ports: