diff --git a/lib/charms/mongodb/v1/helpers.py b/lib/charms/mongodb/v1/helpers.py
index 7c2e52d06..638569073 100644
--- a/lib/charms/mongodb/v1/helpers.py
+++ b/lib/charms/mongodb/v1/helpers.py
@@ -7,7 +7,7 @@
 import secrets
 import string
 import subprocess
-from typing import List
+from typing import List, Optional, Union
 
 from charms.mongodb.v0.mongodb import MongoDBConfiguration, MongoDBConnection
 from ops.model import (
@@ -29,7 +29,7 @@
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 2
+LIBPATCH = 3
 
 # path to store mongodb ketFile
 KEY_FILE = "keyFile"
@@ -260,6 +260,25 @@ def copy_licenses_to_unit():
     )
 
 
+_StrOrBytes = Union[str, bytes]
+
+
+def process_pbm_error(error_string: Optional[_StrOrBytes]) -> str:
+    """Parses pbm error string and returns a user friendly message."""
+    message = "couldn't configure s3 backup option"
+    if not error_string:
+        return message
+    if type(error_string) == bytes:
+        error_string = error_string.decode("utf-8")
+    if "status code: 403" in error_string:  # type: ignore
+        message = "s3 credentials are incorrect."
+    elif "status code: 404" in error_string:  # type: ignore
+        message = "s3 configurations are incompatible."
+    elif "status code: 301" in error_string:  # type: ignore
+        message = "s3 configurations are incompatible."
+    return message
+
+
 def current_pbm_op(pbm_status: str) -> str:
     """Parses pbm status for the operation that pbm is running."""
     pbm_status = json.loads(pbm_status)