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ismailurek2
ismailurek2
New Member
May 11, 2026
Solved

FortiSIEM Content Update 908 “Server Unreachable” Error

  • May 11, 2026
  • 3 replies
  • 67 views

Hello,

 

I am trying to update FortiSIEM content version from 901 to 908, but I receive a “server unreachable” error during the update.

For testing, I allowed all-all access on the firewall for FortiSIEM, but the issue still persists.

Has anyone experienced a similar issue? Are there any specific URLs/FQDNs, ports, or log files that should be checked for FortiSIEM content updates?

 

Best Regards,

İsmail ÜREK

Best answer by ismailurek2

Hi ​@AEK ​@Sheikh, 

Thank you for the information. When I followed your instructions, the issue seemed to be resolved.

After applying the content update procedures on the CLI I provided below, the issue has been resolved.

 

Best Regards,

 

3 replies

AEK
SuperUser
AEK
SuperUser
May 11, 2026

Hello Ismail

From FSM CLI try to connect to the update location and see if it is successful.

telnet update.fortiguard.net 443

This will also reveal of it is a DNS problem or a L3/L4 related issue.

AEK
Sheikh
Staff
Sheikh
Staff
May 11, 2026

Hello ​@ismailurek2 

The answer could vary, but I hope that you have verified the initial troubleshooting. If there is any SSL inspection enabled, try to remove it as well.

The “server unreachable” message usually does not mean generic internet connectivity. In many cases it is caused by one of these:

  • DNS resolution failure
  • TLS/SSL inspection or proxy interference
  • FortiSIEM update repository reachability
  • Incorrect NTP/time sync
  • Certificate validation issues
  • Repository URL changes between releases

If DNS or TLS fails here, the GUI update will also fail. 

Do you see anything suspicious in the FortiSIEM logs ?

Regards,

Sheikh

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ismailurek2
ismailurek2AuthorAnswer
New Member
May 11, 2026

Hi ​@AEK ​@Sheikh, 

Thank you for the information. When I followed your instructions, the issue seemed to be resolved.

After applying the content update procedures on the CLI I provided below, the issue has been resolved.

 

Best Regards,

 

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