Hi Lóránd,
If you're referring to the maximum length of the StringRuleItem
key, please note that this should consist of
UTF8 code that is greater than 127 and consist of US-ascii letters or digits or underscore or
UTF8 code that is greater than 127. There are no specific limits on the
StringRuleItem value. If you're still having an issue, please check
this guide on how to enable logging for the .NET client library. You can share the details privately via Reply privately to author option.