Oracle Solution for Error ora-25109

ORA-25109: standby lock name space has illegal character 'string'

What triggered the Error:

invalid lock name space was specified for the standby database. The lock name space for the standby database can only contain A-Z, 0-9, '_', '#', '$', '.' and '@' characters.

What should we do to fix it:

ange initialization parameter _STANDBY_LOCK_NAME_SPACE to a valid character string.