Não é possível reverter a criptografia; não foi desinstalado

Question

Durante a instalação do CalendarServer-7, recebo o seguinte erro:

Estou no Ubuntu 16.04

ii  openssl                              1.0.2g-1ubuntu4.5                 amd64        Secure Sockets Layer toolkit - cryptographic utility
ii  python-cryptography                  1.2.3-1ubuntu0.1                  amd64        Python library exposing cryptographic recipes and primitives (Python 2)
ii  python3-cryptography                 1.2.3-1                           amd64        Python library exposing cryptographic recipes and primitives (Python 3)

-

-I/usr/include/python2.7 -c src/cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_e7d09016xc302a38b.c
-o build/temp.linux-x86_64-2.7/src/cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_e7d09016xc302a38b.o


src/cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_e7d09016xc302a38b.c:505:6: error: conflicting types for ‘BIO_new_mem_buf’
     BIO *BIO_new_mem_buf(void *, int);
          ^
    In file included from /usr/include/openssl/asn1.h:65:0,
                     from src/cryptography/hazmat/bindings/__pycache__/_Cryptography_cffi_e7d09016xc302a38b.c:220:
    /usr/include/openssl/bio.h:692:6: note: previous declaration of ‘BIO_new_mem_buf’ was here
     BIO *BIO_new_mem_buf(const void *buf, int len);
          ^
    error: command 'x86_64-linux-gnu-gcc' failed with exit status 1

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Por favor, ajude-me a resolver este problema.