Docker build error for repository add

I m using ubuntu:16.04 image for build process

When i tried to build container i got following error

gpg: keyring /tmp/tmp8mkyn_kv/secring.gpg' created gpg: keyring/tmp/tmp8mkyn_kv/pubring.gpg’ created
gpg: requesting key E5267A6C from hkp server
gpg: /tmp/tmp8mkyn_kv/trustdb.gpg: trustdb created
gpg: key E5267A6C: public key “Launchpad PPA for Ond\xc5\x99ej Sur�” imported
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
‘ascii’ codec can’t decode byte 0xc5 in position 92: ordinal not in range(128)
The command ‘/bin/sh -c apt-add-repository ppa:ondrej/php -y’ returned a non-zero code: 1

how can i resolve this

does anyone have idea.