Phones not registering

[dpaquet]

Running into an interesting issue. We're migrating from a premises based CUCM (v11.5) to UCM-G. We've already migrated a couple hundred phones using the factory reset. We just implemented the Bulk Cert export process for both clusters to make the migration faster/easier. We attempted to migrate more phones (8851) to UCM-G and the registration is failing. DHCP is working and we see the TFTP/69 attempt through our FW. We are not seeing the HTTP/TCP 6970 default TFTP attempt at all. With UCM-G Cisco blocks TFTP/69 (FedRamp Policy) so it's not an option. Firmware is the same. Tried Google, Cisco, and other sites to determine what would cause an 8851 to not attempt TFT using HTTP/6970. Firmware is the same as phones already migrated. FW is open to support HTTP/6970. 

[Chris Deren]

Have you looked at the phones' console log for clues on where it's failing?  Those logs are very comprehensive and can provide insight for issues such as this.  

[dpaquet]

Web Access to obtain the logs is not available on UCM-G because of security.