Explanation of the error
This Salesforce error that Gearset is surfacing is usually encountered when deploying a change to a profile.
The change being made to that profile is either the adding of a permission for a feature that is not enabled on the destination org, or removing a permission that Salesforce is seeing as required on the destination org.
Resolution
To resolve this issue, the easiest way is to exclude that particular change from the comparison by unselecting it.
This could be a deletion or an addition of a permission within the profile Salesforce is surfacing the error for.
It is also worth double checking that the same features are enabled on your destination and source orgs to make sure the permission is relevant to the destination org.
Further examples of this Salesforce validation error can be found here:
Disclaimer: This error is returned by Salesforce directly, rather than Gearset. Even so, we offer guidance based on our combined experience with the Metadata API. Where possible, we try to help guide you to fix or avoid this error. In the case that this isn't possible, we may need to direct you to Salesforce support for further clarification.