estos provides the ProCall Enterprise mobile apps only as long as the ProCall version is still in its life cycle.
After the end of life of a ProCall Enterprise version, the mobile apps can no longer be used.

ProCall 6 Enterprise

The grace period for app usage in conjunction with ProCall 6 Enterprise (End of Life 2022) has been extended to . Please switch to a product version that is not yet End of Life as soon as possible. For more information on current ProCall Enterprise versions, see Product lifecycle.

Further information

Current ProCall mobile app version no longer works with ProCall Enterprise