[Bug]: certificate error

[olaulau]

⚠️ 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

certificate error without any reason

Steps to reproduce

don't know exactly the conditions to reproduce this bug, as it doesn't happen on my laptopµ
same configuration :
debian testing
nextcloud-desktop package from the repo (3.5.1-2)
accessing my nextcloud instance which uses a valid letsencrypt SSL cert

I've also seen this bug happenning under windows 10 with an older version the client (fixed after upgrading).

Expected behavior

connect without any error

Which files are affected by this bug

idk

Operating system

Linux

Which version of the operating system you are running.

debian testing

Package

Distro package manager

Nextcloud Server version

21.0.7

Nextcloud Desktop Client version

3.5.1-2

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

Fresh desktop client install

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 Server logs

No response

Additional info

No response

[olaulau]

[ownbee]

Also had similar issue which is now resolved. When I checked the client logs at ./.config/Nextcloud/logs/ I saw a bunch of warnings like:

cannot call unresolved function SSL_CTX_load_verify_dir

I had previously installed openssl 1.1 on my ubuntu 22.04 system which had placed itself as the primary ssl lib using symlik. After I deleted the /usr/local/lib/libssl.so which pointed at /usr/local/lib/libssl.so.1.1 instead of libssl.so.3 (which nextcloud expects) it started working. On my system I had libssl.so.3 installed at /usr/lib/ which is superseded by /usr/local/lib/.

Make sure you have openssl 3 installed.

[neurolag]

I am experiencing the very same issue on Windows.
This is constantly reproducible by doing the following:

• Install Windows 11 (you might want to create a VM for this)
• Install chocolatey using the following command:

  Set-ExecutionPolicy Bypass -Scope Process -Force; [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.ServicePointManager]::SecurityProtocol -bor 3072; iex ((New-Object System.Net.WebClient).DownloadString('https://community.chocolatey.org/install.ps1'))

• Install Nextcloud Client using Chocolatey

  choco install nextcloud-client

• Start Nextcloud and try to log in
• Take note that the certificate is rejected with the error message shown in @olaulau's comment: [Bug]: certificate error #4761 (comment)

However, I found a workaround in the Nextcloud forum:
https://help.nextcloud.com/t/nextcloud-app-untrusted-certificate-ok-in-browser/124532/8

After doing the following:

Invoke-WebRequest https://valid-isrgrootx1.letsencrypt.org/;

Or opening https://valid-isrgrootx1.letsencrypt.org/ in a web browser, it magically works.
I really don't know as to why this fixes the issue.

[joshtrichards]

As noted, this is either a device specific certificate chain matter or broken device libssl/openssl.

Related: #3858

If still experiencing something like this, check previously closed issues with various solutions/workarounds or check the Nextcloud Help Forum - https://help.nextcloud.com