With the legacy FlexLM license server, it was possible to configure a failover license server that could operate on minimal hardware resources.
In contrast, current on-premises deployments require Portal for ArcGIS to manage licensing.
This introduces challenges for non-high-availability (non-HA) environments, as upgrades and patch installations, including faulty patches or network issues, can lead to system downtime. During such periods, users who depend solely on ArcGIS Pro, and do not otherwise require Portal, are unable to work.
This limitation is discussed in the Esri Community thread: ArcGIS Pro license failover with new Named User li... - Esri Community
To address this issue, I propose a lightweight licensing option that does not require deploying a full Portal for ArcGIS HA environment.
Alternatively, ArcGIS Pro could allow temporary offline operation—for example, permitting users to continue working for a limited period (e.g., one day) if a successful login was completed the previous day.
An additional approach could be the introduction of an “emergency mode” for administrators, enabling continued ArcGIS Pro usage during temporary Enterprise outages.
Requiring a full HA deployment solely for licensing purposes is excessive for many use cases, particularly where ArcGIS Pro is the primary application in use.