diff --git a/README.md b/README.md
index b4b453f..50df31b 100644
--- a/README.md
+++ b/README.md
@@ -76,4 +76,7 @@ Use SSL instead of default TLS. Set both to 0 to turn off encryption. (not recom
     - "PARSER_IMAP_SSL=1"
     - "PARSER_IMAP_TLS=0"
 ```
-
+Ignore ERROR: message_string() issue experienced with Exchange Online.
+```yaml
+    - "PARSER_IMAP_IGNORE_ERROR=1"
+```
diff --git a/manifest/usr/bin/dmarcts-report-parser.conf b/manifest/usr/bin/dmarcts-report-parser.conf
index 332e5c9..3443c04 100644
--- a/manifest/usr/bin/dmarcts-report-parser.conf
+++ b/manifest/usr/bin/dmarcts-report-parser.conf
@@ -28,7 +28,7 @@ $imappass         = $ENV{'PARSER_IMAP_PASS'};
 $imapssl          = $ENV{'PARSER_IMAP_SSL'} // '0';         # If set to 1, remember to change server port to 993 and disable imaptls.
 $imaptls          = $ENV{'PARSER_IMAP_TLS'} // '1';         # Enabled as the default and best-practice.
 $tlsverify        = $ENV{'PARSER_IMAP_VERIFY'} // '0';      # Enable verify server cert as the default and best-practice.
-$imapignoreerror  = 0;                                      # set it to 1 if you see an "ERROR: message_string()
+$imapignoreerror  = $ENV{'PARSER_IMAP_IGNORE_ERROR'} // '0';# set it to 1 if you see an "ERROR: message_string()
                                                             # expected 119613 bytes but received 81873 you may
                                                             # need the IgnoreSizeErrors option" because of malfunction
                                                             # imap server as MS Exchange 2007, ...