Error while creating DRMAdditionalHeader

Hello! Today since 3 a.m. ams (5.0.3 r3029 x64) server gives such errors in apache log:

[Mon Apr 06 03:00:00 2015] [info] Failed to configure encryption for fragment 469796 ,segment 70

[Mon Apr 06 03:00:00 2015] [error] mod_f4fhttp [500]: Internal failure: Failed to encrypt fragment.

[Mon Apr 06 03:00:18 2015] [error] mod_f4fhttp [500]: An invalid certificate was passed to DME

[Mon Apr 06 03:00:18 2015] [info] Error while creating DRMAdditionalHeader.

So f4m is present and fine, but drmmeta can not be taken from server (500 error)

In httpd.conf:

<Location /phds-live13>

    HttpStreamingEnabled true

    HttpStreamingLiveEventPath "../applications"

    HttpStreamingContentPath "../applications"

    HdsFmsDirPath ".."

    HttpStreamingF4MMaxAge 2

    HttpStreamingBootstrapMaxAge 2

    HttpStreamingDrmmetaMaxAge 3600

    HttpStreamingFragMaxAge 3600

    Options -Indexes FollowSymLinks

    HttpStreamingEncryptionScope server

    HttpStreamingProtectionScheme PHDS

    PHDSCommonKeyFile "../creds/common-key.bin"

    PHDSVideoEncryptionLevel 1

    PHDSPlaybackExpiration 24Hours

    PHDSOutputProtection None

    PHDSEnableKeyRotation false

</Location>

I also attempted to make a new key (with restart of ams server) - ./scramble -KeyGen 16 -f /opt/adobe/ams/creds/common-key.bin  - still no luck.

What is the problem?