UCS backup not loading Big IP DNS pool

Hello,

Could you please confirm if the ucl file s not corrupted. or we need to check if there is any compatibility issues while upgrading from 13 to 15. also you can try to restore the ucs via CLI than GUI

load sys ucs /path/to/your/ucs_file.ucs

BR

Aswin

Network_Virtuoso 

you should consider using platform-migrate keyword if your test LAB F5 and real/prof f5 are on different platform/hardware series etc. Also if you have a different license on prod UCS will try to restore that license on your LAB test F5 it will fail.
You have to use no-license keyword in the same load sys ucs command

tmsh
load sys ucs <filename> platform-migrate

To restore an F5 BIG-IP configuration using a UCS file while migrating to a different platform and bypassing license checks, use the tmsh command with the load sys ucs option, including no-license and platform-migrate

tmsh

load sys ucs <ucs_file_name> no-license platform-migrate

================

Note
Replace <ucs_file_name> with the actual name of your UCS file. 
no-license: This option tells the system to ignore the license check during the restore. 
platform-migrate: This option allows you to migrate the configuration to a different BIG-IP platform. 

Example: load sys ucs myconfig.ucs no-license platform-migrate 

https://my.f5.com/manage/s/article/K82540512
https://my.f5.com/manage/s/article/K13132

test and let me know for any further help

Hello,

Can you try command "tmsh load sys gtm-only"