[Bug]: Handshake failed: An unsupported function was requested since upgrade to 3.16.0

[disaderp]

⚠️ Before submitting, please verify the following: ⚠️

• This is a bug, not a question or a configuration issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server and Desktop Client are up to date. See Server Maintenance and Release Schedule and Desktop Releases for supported versions.
• I agree to follow Nextcloud's Code of Conduct

Bug description

Since upgrade to 3.16.0 Nextcloud client cannot connect to previously functioning instance:

Steps to reproduce

1. Open Nextcloud 3.16.0

Expected behavior

n/a

Which files are affected by this bug

webflowcredentials.cpp

Operating system

Windows

Which version of the operating system you are running.

Windows 10

Package

Official Windows MSI

Nextcloud Server version

30.0.6

Nextcloud Desktop Client version

3.16.0

Is this bug present after an update or on a fresh install?

Updated to a major version (ex. 3.3.6 to 3.4.0)

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

Are you using an external user-backend?

• Default internal user-backend
• LDAP/ Active Directory
• SSO - SAML
• Other

Nextcloud Client logs

C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\libsync\configfile.cpp:749 ]:	Default update channel is "stable"
2025-03-11 18:16:02:790 [ warning nextcloud.sync.credentials.keychainchunk C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\libsync\creds\keychainchunk.cpp:360 ]:	Unable to read "Nextcloud_proxy-password" chunk "0" "Password entry not found"
2025-03-11 18:16:02:790 [ warning nextcloud.sync.credentials.keychainchunk C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\libsync\creds\keychainchunk.cpp:360 ]:	Unable to read "Nextcloud_proxy-password" chunk "0" "Password entry not found"
2025-03-11 18:16:02:806 [ info nextcloud.sync.clientsideencryption C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\libsync\clientsideencryption.cpp:1007 ]:	Initializing
2025-03-11 18:16:02:806 [ info nextcloud.sync.clientsideencryption C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\libsync\clientsideencryption.cpp:1009 ]:	No Client side encryption available on server.
2025-03-11 18:16:02:806 [ info nextcloud.sync.accessmanager C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\libsync\accessmanager.cpp:74 ]:	6 "PROPFIND" "https://REDACTED/remote.php/dav/files/REDACTED/" has X-Request-ID "bb467dc6-beb7-41cc-a887-39386c62c092"
2025-03-11 18:16:02:806 [ info nextcloud.sync.networkjob C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\libsync\abstractnetworkjob.cpp:364 ]:	OCC::LsColJob created for "https://REDACTED" + "/" ""
2025-03-11 18:16:02:972 [ info nextcloud.sync.credentials.webflow C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\gui\creds\webflowcredentials.cpp:406 ]:	request finished
2025-03-11 18:16:02:972 [ warning nextcloud.sync.networkjob C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\libsync\abstractnetworkjob.cpp:184 ]:	SslHandshakeFailedError:  "Nawiązanie sesji SSL zakończone błędem: Handshake failed: An unsupported function was requested"  : can be caused by a webserver wanting SSL client certificates
2025-03-11 18:16:02:973 [ warning nextcloud.sync.networkjob C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\libsync\abstractnetworkjob.cpp:223 ]:	QNetworkReply::SslHandshakeFailedError "Nawiązanie sesji SSL zakończone błędem: Handshake failed: An unsupported function was requested" QVariant(Invalid)
2025-03-11 18:16:02:973 [ warning nextcloud.sync.credentials.webflow C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\gui\creds\webflowcredentials.cpp:207 ]:	QNetworkReply::SslHandshakeFailedError
2025-03-11 18:16:02:973 [ warning nextcloud.sync.credentials.webflow C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\gui\creds\webflowcredentials.cpp:208 ]:	"Nawiązanie sesji SSL zakończone błędem: Handshake failed: An unsupported function was requested"
2025-03-11 18:16:02:973 [ info nextcloud.sync.networkjob.lscol C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\libsync\networkjobs.cpp:386 ]:	LSCOL of QUrl("https://REDACTED/remote.php/dav/files/REDACTED/") FINISHED WITH STATUS "SslHandshakeFailedError Nawiązanie sesji SSL zakończone błędem: Handshake failed: An unsupported function was requested"
2025-03-11 18:16:19:499 [ info nextcloud.gui.folder.manager C:\Users\User\AppData\Local\Temp\windows-29045\client-building\desktop\src\gui\folderman.cpp:1006 ]:	Etag poll timer timeout

Additional info

Instance works properly in browser and was working before the upgrade.

[m3g33]

This bug has been resolved in #7994 (comment).
You can use the daily build until the next stable version is released.

[disaderp]

Sorry for reporting it twice, I didn't think to look in closed issues already.