PAN OS 8 Could not connect to Cloud : SSL/TLS Authentication Failed

[BKerstiens]

After an upgrade to PAN OS 8 i keep getting this critical event and i've seen it on multiple firewalls. 

domain: 1
receive_time: 2017/02/27 10:20:46
serial: xxxxxxxxxx
seqno: 3449381
actionflags: 0x0
type: SYSTEM
subtype: general
config_ver: 0
time_generated: 2017/02/27 10:20:46
dg_hier_level_1: 0
dg_hier_level_2: 0
dg_hier_level_3: 0
dg_hier_level_4: 0
vsys_name:
device_name: xxxxxxxxxx
vsys_id: 0
vsys:
eventid: auth-fail
object:
fmt: 0
id: 0
module: general
severity: critical
opaque: Could not connect to Cloud : SSL/TLS Authentication Failed

[BPry]

I would try to reregister and see if that fixes the issue, also make sure your licenses are actually up-to-date and that you have active licenses.