Back to My Mac: BTMM kMMServiceFailureNotification About a week ago iCloud's Back to My Mac service silently stopped working and will no longer start.

I discovered an error icon in System Preference's iCloud panel reporting the error: Back to My Mac isn't working because it couldn't start properly.

Following the trouble shooting steps provided by Apple has not fixed the problem. This includes restarting, and signing out &amp; back into iCloud. An Apple support discussion thread, I cannot start Back To My Mac Since Wed Last Week, suggests this is not an isolated problem.

The system.log messages at the time of attempted enabling suggests an error occurred:

Jan 16 09:59:46 Mac-Pro com.apple.preferences.icloud.remoteservice[731]: AOSKit ERROR: LH request failed, url=https://p33-btmm.icloud.com:443/v1/hello, requestHeaders=
    {
        "Accept-Language" = "en-us";
        Authorization = "...";
        "X-Mme-Client-Info" = "&lt;[redacted]&gt; &lt;Mac OS X;10.11.2;15C50&gt; &lt;com.apple.AOSKit/232 (com.apple.systempreferences/14.0)&gt;";
        "X-Mme-Country" = GB;
        "X-Mme-Device-Id" = "[redacted]";
        "X-Mme-Timezone" = CET;
    },
    error=Error Domain=AOSErrorDomain Code=1000 "(null)" UserInfo={HttpStatusCode=503, DialogInfo={
        DialogType = Unknown;
    }}, httpStatusCode=503
Jan 16 09:59:46 Mac-Pro com.apple.preferences.icloud.remoteservice[731]: [AOSAccounts] : BTMM operation not successful 
Jan 16 09:59:46 Mac-Pro com.apple.preferences.icloud.remoteservice[731]: [AOSAccounts] : BTMM kMMServiceFailureNotification dictionary &lt;CFBasicHash 0x7f921e2ba590 [0x7fff7c6cd440]&gt;{type = mutable dict, count = 2,
    entries =&gt;
        0 : &lt;CFString 0x7fff7b7cc170 [0x7fff7c6cd440]&gt;{contents = "ServiceFailureErrorKey"} = Error Domain=AOSErrorDomain Code=1000 "(null)" UserInfo={HttpStatusCode=503, DialogInfo={
        DialogType = Unknown;
    }}
        2 : &lt;CFString 0x7fff7b7cc110 [0x7fff7c6cd440]&gt;{contents = "ServiceFailureTypeKey"} = &lt;CFString 0x7fff7b7cc130 [0x7fff7c6cd440]&gt;{contents = "ServiceFailureTypeEnable"}
    }


I have reported the bug to Apple as rdar://24219994

Is there any solution?
In response to your question "Is there any solution?": Yes

Initial Feedback: I appear to have the same problem, which appeared out of the blue and which I noticed only on around 13 Jan (4 days prior). It appeared to have occurred at the same time as the last in a 3-4 week series of occasional spurious iCloud ID errors, requiring me to enter my iCloud password on each occasion. Back to my Mac is not accessible on any of the 3 macs using my personal account.

I spent 90 minutes on the phone with Apple Support. The problem could not be resolved immediately and was escalated to the level of the engineering staff for offline investigation.

Update: 3 days later BTMM was working correctly on all my machines, having been fixed at the Apple end. No explanation as yet as to the cause or how resolved. I recommend you contact Apple Support directly