Today I got same issue and @pujanm's suggestion is solved the problem.
# apt-get update
Get:1 http://archive.ubuntu.com/ubuntu bionic InRelease [242 kB]
Get:2 http://security.ubuntu.com/ubuntu bionic-security InRelease [88,7 kB]
Public bug reported:
# openssl s_client -connect kaski.kahramanmaras.bel.tr:443
CONNECTED(0003)
140626416125600:error:140773E8:SSL
routines:SSL23_GET_SERVER_HELLO:reason(1000):s23_clnt.c:762:
---
no peer certificate available
---
No client certificate CA names sent
---
SSL handshake has read
Public bug reported:
update-manager -d give error below while upgrading 12.04 to 14.04:
Could not calculate the upgrade
An unresolvable problem occurred while calculating the upgrade.
This can be caused by:
* Upgrading to a pre-release version of Ubuntu
* Running the current pre-release vers
Same issue with different selection in tasksel:
After installed minimal ubuntu server 32 12.04 I ran tasksel and select
"Basic Ubuntu Server, Mythbuntu Additional Roles, Mythbuntu Frontend
and Mythbuntu Master Backend" packages to install. On installation
process tasksel exits with "aptitude fail
