How do I resolve this error?
The obvious question: have you verified that you, in fact, have the same patchlevel on both systems?
How exactly did you do that?
There is also a known issue in some versions of R80.10 (not sure's relevant since you did not mention your version at all): Management HA fails to synchronize with "The Security Management Servers contain different Hotfixes" error
Retrieving data ...