After upgrading the Cloud Enabled Management (CEM) Internet Gateway from 7.5 to 7.6 the logs on the Internet Gateway show numerous errors including.
Client xxx.xxx.x.xx: Certificate Verification: Error (20): unable to get local issuer certificate (proto:TLSv1; certCN:/CN=Client.example.com; serial:76EF39DD1307B4BF31EBB96F02E1A2A30994A5E4; issuer:/CN=NSserver.example.com Agent)
ITMS 7.x, 8.x
Certficate and hash information on the gateway was not updated.
Delete the SMP server and site servers from the list of servers in the Internet Gateway Manager and then add them back in.