Plesk 12.5 to Onyx issue

Hi,
i got 2 servers. On of of them Ubuntu 16, upgrade was successfull after 3 minutes.
On the other, Ubuntu 14.04.5 i tried several times to upgrade without success. An error remains.

I'm not strong enough to analyse the attached log.
I tried the repair tool , but no problem was detected but a little right files warning at the root directory of my domain.

Any help would be welcome.
Thanks in advance.