When trying to add/change a CICS transaction to AD that has one of the ten Special AD characters like the following AD definition:

DN: CN=##FB,CN=TCICSTRN,CN=Enterprise Server Resources,CN=Micro Focus,CN=Program Data,DC=local

you will receive the following error messages:

Add error on entry starting on line xx: Invalid DN Syntax
The server side error is: 0x57 The parameter is incorrect.
The extended server error is:
00000057: LdapErr: DSID-0C0910A4, comment: Error processing name, data 0, v4563
An error has occurred in the program

Full article: https://portal.microfocus.com/s/article/KM000017331