I have the same issue with AddressBook on 2 Macs syncing to the same IMAP server. This worked perfectly over 4-5 years. For a couple of months, I now have this annoying timeouts when editing my address book.
I sync 3 accounts with one CardDAV server. Sync as such works fine. All changes done (after waiting for the timeouts) are properly updated and synced to my other Mac, my iPhone and iPad. So the network connection as such is fine and the configured address is reachable.
When editing one address book entry, the log file creates 3 attempts of the following entries, repeated 6 times; a total of 18 timeouts (the number of the 6 repeats is probably dependent on the number of details of one address book entry). Details of the log file are as follows:
19/12/15 01:29:10.323 com.apple.AddressBook.InternetAccountsBridge[5125]: dnssd_clientstub ConnectToServer: connect()-> No of tries: 3
19/12/15 01:29:10.341 sandboxd[137]: ([5125]) com.apple.Addres(5125) deny network-outbound /private/var/run/mDNSResponder
19/12/15 01:29:11.328 com.apple.AddressBook.InternetAccountsBridge[5125]: dnssd_clientstub ConnectToServer: connect() failed path:/var/run/mDNSResponder Socket:4 Err:-1 Errno:1 Operation not permitted
Details of the 2nd entry are as follows:
com.apple.Addres(5125) deny network-outbound /private/var/run/mDNSResponder
Process: com.apple.Addres [5125]
Path: /System/Library/Frameworks/AddressBook.framework/Versions/A/XPCServices/com.apple.AddressBook.InternetAccountsBridge.xpc/Contents/MacOS/com.apple.AddressBook.InternetAccountsBridge
Load Address: 0x10d717000
Identifier: com.apple.AddressBook.InternetAccountsBridge
Version: 1679.4 (9.0)
Build Info: 1-AddressBook_frameworks_64bit~1679004000000000
Code Type: x86_64 (Native)
Parent Process: launchd [1]
Date/Time: 2015-12-19 01:29:10.324 +0100
OS Version: Mac OS X 10.11.2 (15C50)
Report Version: 8
Thread 0:
0 libsystem_kernel.dylib 0x00007fff87b2a65e __connect_nocancel + 10
1 libsystem_dnssd.dylib 0x00007fff9704aac0 DNSServiceQueryRecord + 61
2 InternetAccounts 0x00007fff90654688 -[IADNSService beginQuerySync] + 636
3 InternetAccounts 0x00007fff90624340 +[IAAccount aListPluginIDForSettings:] + 1705
4 com.apple.AddressBook.InternetAccountsBridge 0x000000010d7182e9
5 CoreFoundation 0x00007fff85cfc17c __invoking___ + 140
6 CoreFoundation 0x00007fff85cfbfce -[NSInvocation invoke] + 286
7 Foundation 0x00007fff94f5fcdf __NSXPCCONNECTION_IS_CALLING_OUT_TO_EXPORTED_OBJECT__ + 17
8 Foundation 0x00007fff94f5f5d9 -[NSXPCConnection _decodeAndInvokeMessageWithData:] + 1123
9 Foundation 0x00007fff94f5f0a7 message_handler + 705
10 libxpc.dylib 0x00007fff96e65396 _xpc_connection_call_event_handler + 35
11 libxpc.dylib 0x00007fff96e6500f _xpc_connection_mach_event + 2198
12 libdispatch.dylib 0x00007fff948834ca _dispatch_client_callout4 + 9
13 libdispatch.dylib 0x00007fff9488393c _dispatch_mach_msg_invoke + 555
14 libdispatch.dylib 0x00007fff94880134 _dispatch_queue_drain + 1207
15 libdispatch.dylib 0x00007fff94882293 _dispatch_mach_invoke + 735
16 libdispatch.dylib 0x00007fff94880134 _dispatch_queue_drain + 1207
17 libdispatch.dylib 0x00007fff9488663b _dispatch_queue_invoke + 549
18 libdispatch.dylib 0x00007fff9487b33f _dispatch_client_callout + 8
19 libdispatch.dylib 0x00007fff9487f1cf _dispatch_root_queue_drain + 1890
20 libdispatch.dylib 0x00007fff9487ea34 _dispatch_worker_thread3 + 91
21 libsystem_pthread.dylib 0x00007fff8b5ca68f _pthread_wqthread + 1129
22 libsystem_pthread.dylib 0x00007fff8b5c8365 start_wqthread + 13
Binary Images:
0x10d717000 - 0x10d718fff com.apple.AddressBook.InternetAccountsBridge (9.0 - 1679.4) <b81763bd-9e7e-377c-b3a2-1c3074c3ce6e> /System/Library/Frameworks/AddressBook.framework/Versions/A/XPCServices/com.apple.AddressBook.InternetAccountsBridge.xpc/Contents/MacOS/com.apple.AddressBook.InternetAccountsBridge
0x7fff85cc3000 - 0x7fff86139fff com.apple.CoreFoundation (6.9 - 1256.14) <068d1ba9-3859-34c7-986a-97edf739c5c8> /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation
0x7fff87b14000 - 0x7fff87b32fff libsystem_kernel.dylib (3248.20.55) <0e688457-4915-36dd-8798-5c2edee3f1a3> /usr/lib/system/libsystem_kernel.dylib
0x7fff8b5c7000 - 0x7fff8b5d0ff7 libsystem_pthread.dylib (138.10.4) <327cecd0-b881-3153-8fcc-4fd4818b7f16> /usr/lib/system/libsystem_pthread.dylib
0x7fff90620000 - 0x7fff90689fff com.apple.framework.internetaccounts (2.1 - 210) <ecb2be85-fd74-3fd0-9f14-b0ab713b3acd> /System/Library/PrivateFrameworks/InternetAccounts.framework/Versions/A/InternetAccounts
0x7fff94879000 - 0x7fff948a6fff libdispatch.dylib (501.20.1) <324c9189-2af3-3356-847f-6f4ce1c6e901> /usr/lib/system/libdispatch.dylib
0x7fff94ee8000 - 0x7fff9523cff7 com.apple.Foundation (6.9 - 1256.1) <66106cc9-9d97-3846-88d8-4bf6bb508296> /System/Library/Frameworks/Foundation.framework/Versions/C/Foundation
0x7fff96e5e000 - 0x7fff96e87fff libxpc.dylib (756.20.4) <61ab4610-9304-354c-9e9b-d57198ae9866> /usr/lib/system/libxpc.dylib
0x7fff97047000 - 0x7fff9704fffb libsystem_dnssd.dylib (625.20.4) <945b5fb1-da91-3d45-a961-a8fad53c1e7e> /usr/lib/system/libsystem_dnssd.dylib