Hi,
I’m experiencing a persistent Battle.net Desktop App issue on Windows 11 with error BLZBNTBNA00000005 (“Battle.net Update Agent went to sleep”). Occasionally I have also seen BLZBNTBNA00000006.
Versions:
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Battle.net Desktop App: 2.52.10.17731
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Battle.net Agent: 2.41.0.9775
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OS: Windows 11
The important part is that I have been able to reproduce and isolate the failure to the Battle.net Agent’s network/TLS connection.
A fresh Agent log shows:
Agent started as Administrator
Argument[0]: '--session=12194678551631146587'
Checking Network Connection status to https://eu.version.battle.net/agent
followed by:
Network Connection Response to https://eu.version.battle.net/agent - CURL error: 35, Status Code: 0
The Agent then shuts down because no Battle.net client is connected.
I also have Agent curl logs showing:
CurlError 35 from "https://eu.version.battle.net/v2/summary" with message "schannel: failed to receive handshake, SSL/TLS connection failed"
Control test:
This is where the issue becomes unusual. On the exact same PC, 32-bit Windows curl using Schannel successfully connects to the same Battle.net EU version infrastructure:
C:\Windows\SysWOW64\curl.exe -v https://eu.version.battle.net/v2/summary -o NUL
This resolves the endpoint, establishes the connection, successfully handles the server-requested TLS renegotiation, and returns:
HTTP/1.1 200 OK
64-bit Windows curl also works. TLS 1.2 and TLS 1.3 tests succeed as well.
Therefore Windows networking and Schannel are capable of establishing the connection, while Battle.net Agent 2.41.0.9775 consistently fails its own Schannel TLS connection with CURL error 35.
I also performed another controlled test involving Agent startup. Battle.net’s switcher logged:
Process launch failed for 'C:/ProgramData/Battle.net/Agent/Agent.9775/Agent.exe'
However, the exact same signed Agent executable can be launched manually, both elevated and non-elevated. I also launched it manually using the exact --session argument recorded by the Battle.net switcher.
In that case the Agent starts normally and initializes, but then reproduces the same network failure:
Checking Network Connection status to https://eu.version.battle.net/agent
CURL error: 35, Status Code: 0
Already tested / ruled out:
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Complete Battle.net reinstall and Battle.net ProgramData/cache removal
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Multiple network connections
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DNS changes
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WinHTTP/system proxy configuration
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Windows Firewall
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Windows Defender temporarily disabled
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Windows clean boot with non-Microsoft services disabled
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New local Windows administrator account
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Windows system time synchronization
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SFC and DISM (system files now clean)
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WMI repository verification (
winmgmt /verifyrepositoryreports the repository is consistent) -
Battle.net.exe Authenticode signature is valid
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Battle.net Update Helper service can start successfully
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TCP connectivity to the Battle.net endpoint on port 443 succeeds
I have also confirmed that the Agent is 32-bit, and a successful 32-bit Windows network test uses the same Windows Schannel version.
Battle.net itself can open and log in, and features such as the friends list and Shop can work, but the Update Agent connection fails.
Blizzard Support ticket EU105813458 contains the diagnostic logs and previous troubleshooting. GM support advised me to continue the investigation here because they cannot provide further technical troubleshooting.
Has anyone encountered this specifically with Agent 2.41.0.9775, or can someone from the Battle.net Desktop App team investigate why the Agent’s Schannel/curl implementation fails the TLS handshake while Windows 32-bit curl succeeds against the same Battle.net infrastructure?
I can provide additional Agent/curl logs or run targeted diagnostic tests if needed.