Strategy Server Activation is a licensing technology that ensures that installations of Strategy server products are authentic and have been legitimately licensed. Server Activation registers each Server Installation with Strategy and locks the installation to a specific machine. For more details regarding Strategy Server Activation, refer to the Strategy Licensing Site (https://licensing.Strategy.com).
The following Knowledge Base technical note outlines the circumstances under which Strategy Server Activation is required:
KB14333 (KB5300-802-0808) - What are the circumstances under which Strategy Server Activation is required?
The most likely cause of frequent deactivations (which results in a prompt for re-activation each time) is Cause #5 listed in the above-mentioned technical note - unique machine identifier changes. Causes #1 - #4 are based upon events that would be known a priori (self evident propositions). For a windows machine, the unique machine identifier is the Network Ethernet Card MAC Address.
The unique machine identifier is stored in the Activate.xml file as Host ID (this field is encrypted). Merely attempting to track down such changes between the Activate.xml files (between this activation and a subsequent one) usually does not help with the diagnosis of the problem.
Enhanced logging can be enabled to gain more insight on unique machine identifier changes as the source of deactivation:

After enabling this diagnostic, reproduce the issue and send the logs to Strategy Technical Support, along with Activate.xml, mstr.hist and mstr.bhv files.
NOTE: It is recommended to have the MAQueryEnvironment diagnostic logged into the DSSErrors.log, so that it is easier to co-ordinate with other activities of Intelligence Server. Turn off this diagnostic once the testing is done.