If you have an Online* License, then each time you call one of the counter-increasing methods (full list of these methods is in FRE Help, chapter "Licensing → Methods which Increase the License Counter") FineReader Engine attempts to connect ABBYY licensing server by the Internet. If the connection fails, then you will receive an error message 

Failed to communicate with the online licensing service.

If you run your FineReader Engine or FlexiCapture Engine application on a computer with strict firewall settings, you may wonder what IPs to allow to make Online protection functional.

In such case, please enable *.abbyy.com and ports 80, 443.

 If your firewall type does not allow you using mask *.abbyy.com, then please use the following machine names**:

• account.abbyy.com
• personal-cloud.abbyy.com
• license-cloud.abbyy.com
• us-license-cloud.abbyy.com
• Admin-cloud.abbyy.com
• mail-cloud.abbyy.com
• payment-cloud.abbyy.com

Please don't bind your firewall rules to IPs. The IPs are volatile and could be changed without any warnings. 

Please note, that you may also receive the error "Failed to load Engine with online licensing due to a timeout". In such a case, please apply the same procedure.

* "Online" license is a former "Cloud" license until FineReader Engine 12 Release 3 and actual for FlexiCapture Engine 12. 

** Please note that these addresses are not intended to be pinged. To check the Licensing service availability, please follow the instructions from the How to check the availability of a Licensing Service for Online Licenses article.