Couchbase 2.5 WebUI not available. Some cli commands are not working

I had a cluster of one couchbase 2.5 server( “version”: “2.5.0-1059-rel-enterprise”). OS is Ubuntu 12.04 x64.
After adding two additional servers cluster WebUI stopped working.
After authenticating I recieve the following: "Lost connection to server at server.name:8091. Repeating in 2 seconds. Retry now"
Some cli commands stopped working:
/opt/couchbase/bin/couchbase-cli server-list -c 1.2.3.4:8091 -u user -p password
ERROR: command: server-list: 1.2.3.4:8091, 'error_msg’
The same output is generated when I try to remove new servers or to rebalance.

Here’s what I see in logs:

[menelaus:warn,2014-02-17T22:19:59.415,ns_1@1.2.3.4:<0.12279.0>:menelaus_web:loop:164]Server error during processing: [“web request failed”,
{path,"/pools/default"},
{type,throw},
{what,{json_encode,{bad_term,{fromHour,3}}}},
{trace,
[{io_lib_pretty,cind_tag_tuple,7},
{io_lib_pretty,cind_element,7},
{io_lib_pretty,cind_list,7},
{io_lib_pretty,cind_element,7},
{io_lib_pretty,cind_list,7},
{io_lib_pretty,cind_element,7},
{io_lib_pretty,cind_list,7},
{io_lib_pretty,cind_element,7}]}]

Can you give output of the following command, using the credentials of your host (I saw you already showed the output on 1 host, can you share the output from the other hosts?).

root@ubu-123:~# /opt/couchbase/bin/couchbase-cli server-list -c 10.3.3.4:8091 -u Administrator -p 123456

Also, did you confirm your firewall / iptables is disabled?
Is this a fresh clean install? or an upgrade?

Actually I found the cause of my problem.
It is http://www.couchbase.com/issues/browse/MB-10227
I disabled scheduled compaction and WEBUI started working.