When subscription is "enabled" in native client then the server endpoint name (host name + port) is truncated if exceeds 99 characters resulting with failed connections towards servers (see logs in attachment). When subscription is "disabled" everything worked fine for what I tested. Also I performed some tests with java client and haven't found such limitation on endpoint name length.
Endpoint name (e.g. server host name) + port is truncated within function addEP:
Maximum length of FQDN according to RFC 2181:
The DNS itself places only one restriction on the particular labels
that can be used to identify resource records. That one restriction
relates to the length of the label and the full name. The length of
any one label is limited to between 1 and 63 octets. A full domain
name is limited to 255 octets (including the separators).
Due to above requirement the function addEP should not limit or truncate endpoint name.