diff --git a/src/epplibwrapper/errors.py b/src/epplibwrapper/errors.py
index 2b7bdd255..4ded1e5a7 100644
--- a/src/epplibwrapper/errors.py
+++ b/src/epplibwrapper/errors.py
@@ -62,9 +62,10 @@ class RegistryError(Exception):
         - 2501 - 2502 Something malicious or abusive may have occurred
     """
 
-    def __init__(self, *args, code=None, **kwargs):
+    def __init__(self, *args, code=None, msg=None,**kwargs):
         super().__init__(*args, **kwargs)
         self.code = code
+        self.msg = msg
 
     def should_retry(self):
         return self.code == ErrorCode.COMMAND_FAILED
diff --git a/src/registrar/admin.py b/src/registrar/admin.py
index 40d4befb5..6bafbab08 100644
--- a/src/registrar/admin.py
+++ b/src/registrar/admin.py
@@ -2916,18 +2916,17 @@ class DomainAdmin(ListHeaderAdmin, ImportExportModelAdmin):
         except RegistryError as err:
             # Using variables to get past the linter
             message1 = f"Cannot delete Domain when in state {obj.state}"
-            message2 = "This subdomain is being used as a hostname on another domain"
             # Human-readable mappings of ErrorCodes. Can be expanded.
             error_messages = {
                 # noqa on these items as black wants to reformat to an invalid length
                 ErrorCode.OBJECT_STATUS_PROHIBITS_OPERATION: message1,
-                ErrorCode.OBJECT_ASSOCIATION_PROHIBITS_OPERATION: message2,
+                ErrorCode.OBJECT_ASSOCIATION_PROHIBITS_OPERATION: err.msg,
             }
 
             message = "Cannot connect to the registry"
             if not err.is_connection_error():
                 # If nothing is found, will default to returned err
-                message = error_messages.get(err.code, err)
+                message = error_messages[err.code]
             self.message_user(request, f"Error deleting this Domain: {message}", messages.ERROR)
         except TransitionNotAllowed:
             if obj.state == Domain.State.DELETED:
diff --git a/src/registrar/models/domain.py b/src/registrar/models/domain.py
index 348ccf3ad..f4922bfdd 100644
--- a/src/registrar/models/domain.py
+++ b/src/registrar/models/domain.py
@@ -1066,7 +1066,7 @@ class Domain(TimeStampedModel, DomainHelper):
             if host.domain != self:
                 logger.error("Host %s in use by another domain: %s", host.name, host.domain)
                 raise RegistryError(
-                    "Host in use by another domain: {}".format(host.domain),
+                    msg="Host in use by another domain: {}".format(host.domain),
                     code=ErrorCode.OBJECT_ASSOCIATION_PROHIBITS_OPERATION,
                 )