SIP account on the Yealink T46U suddenly Not Registered

[kmsfn]

I have an issue with Yealink T46U.
I use encrypted cfgs and autoprovisioning from TFTP-server every day, everything was fine but after the next autoprovisioning the SIP-account was not registered.
If I type credentials manually it works. Seems I have autoprovisioning issue.
Could you please tell why this can happen and how to avoid it in the future?

Here is the log:

<131>Oct 22 13:18:35 ATP [886.901]: DURL<3+error > [DCMN]download common error, errcode:68.
<131>Oct 22 13:18:35 ATP [886.901]: ATP <3+error > tftp to file failed, code = -168, msg = , retry = 1
<131>Oct 22 13:18:35 ATP [886.901]: DURL<3+error > [DCMN]download common error, errcode:68.
<131>Oct 22 13:18:35 ATP [886.901]: ATP <3+error > tftp to file failed, code = -168, msg = , retry = 1
<131>Oct 22 13:18:41 ATP [886.901]: DURL<3+error > [DCMN]download common error, errcode:68.
<131>Oct 22 13:18:41 ATP [886.901]: ATP <3+error > tftp to file failed, code = -168, msg = , retry = 1
<131>Oct 22 13:18:41 ATP [886.901]: DURL<3+error > [DCMN]download common error, errcode:68.
<131>Oct 22 13:18:41 ATP [886.901]: ATP <3+error > tftp to file failed, code = -168, msg = , retry = 1
<131>Oct 22 13:18:41 ATP [886.901]: ATP <3+error > get AES Security enc fail.
<131>Oct 22 13:18:41 ATP [886.901]: ATP <3+error > Only Update file_decryptd configs!
<131>Oct 22 13:18:41 ATP [886.901]: ATP <3+error > Decrypt file fail
<131>Oct 22 13:18:47 ATP [886.901]: DURL<3+error > [DCMN]download common error, errcode:68.
<131>Oct 22 13:18:47 ATP [886.901]: ATP <3+error > tftp to file failed, code = -168, msg = , retry = 1
<131>Oct 22 13:18:47 GUI [671:671]: APP <3+error > 927.385.160:from[app_vpPhone] sync[0] msg[395306][1][0] size[4] target[0xc4af3700] not found