no upgrade version since Sophos XG SFOS 17.5.12 MR-12

Question

Hello, 
 I have a version of Sophos XG "SFOS 17.5.12 MR-12", and I no longer have an update offered by Sophos, when I click on "search for new firmware", I have the message next: "Search for new firmware failed". Why does my Sophos no longer check for new firmware versions. So I cannot upgrade to version 18. 
 
 thank you for your help

emmosophos · Answer

Hello there, 
 Thank you for contacting the Sophos Community. 
 Check under System >> Administration >> Central Management. If this one is turned on, turn it off, and click again under System >> Backup & Firmware >> Firmware >> Check for new Firmware 
 If the issue persists check the /u2d.log for any clues. 
 /log/u2d.log 
 Regards,