Infrequent during desktop sync (error:140E0197) SSL

Since my migration from owncloud 10 to nextcloud 12…18 next cloud desktop sync is infrequently causing sync errors. “Öffnen eines Ordners ist ein Fehler aufgetreten. Beim Lesen ist ein Fehler aufgetreten: error:140E0197:SSL routines:SSL_shutdown:shutdown while in init.” This message in the main bar (above the directory list) appears as under a specific sync directory. The message in the main bar disappears after some seconds, nextcloud checks a specific folder for updates, and throws this message. There is no more sync activity after throwing of the error. The point of time when the message is thrown is variable in time and according to the file folder.
I have three sync directories added. One with many files and subfolders and two other with only a few files. The error occurs permanently with the large sync directory but seldom with the smaller syncs.


[_csync_detect_update 	Checking for rename based on fileid 00015***ocn53m****dy
[_csync_detect_update 	file: path2/path3, instruction: INSTRUCTION_NEW <<=
[OCC::AccessManager::createRequest 	6 "PROPFIND" "https://example.org/owncloud/remote.php/dav/files/user/path1/path2/path3" has X-Request-ID "6abb***5-4**b-4**9-b***8-02b****85da"
[OCC::AbstractNetworkJob::start 	OCC::LsColJob created for "https://example.org/owncloud" + "/path1/path2/path3" "OCC::DiscoverySingleDirectoryJob"
[OCC::WebFlowCredentials::slotFinished 	request finished
[OCC::AbstractNetworkJob::slotFinished 	QNetworkReply::UnknownNetworkError "Beim Lesen ist ein Fehler aufgetreten: error:140E0197:SSL routines:SSL_shutdown:shutdown while in init" QVariant(int, 207)
[OCC::WebFlowCredentials::stillValid 	QNetworkReply::UnknownNetworkError
[OCC::WebFlowCredentials::stillValid 	"Beim Lesen ist ein Fehler aufgetreten: error:140E0197:SSL routines:SSL_shutdown:shutdown while in init"
[OCC::LsColJob::finished 	LSCOL of QUrl("https://example.org/owncloud/remote.php/dav/files/user/path1/path2/path3") FINISHED WITH STATUS "UnknownNetworkError Beim Lesen ist ein Fehler aufgetreten: error:140E0197:SSL routines:SSL_shutdown:shutdown while in init"
[OCC::LsColXMLParser::parse 	ERROR "Vorzeitiges Ende des Dokuments." ""
[OCC::DiscoverySingleDirectoryJob::lsJobFinishedWithErrorSlot 	LSCOL job error "Beim Lesen ist ein Fehler aufgetreten: error:140E0197:SSL routines:SSL_shutdown:shutdown while in init" 207 QNetworkReply::UnknownNetworkError
[csync_ftw 	opendir failed for path2/path3 - errno 5
[OCC::SyncEngine::handleSyncError 	ERROR during  csync_update :  "Beim Öffnen eines Ordners ist ein Fehler aufgetreten. Beim Lesen ist ein Fehler aufgetreten: error:140E0197:SSL routines:SSL_shutdown:shutdown while in init"
[OCC::ActivityWidget::addError 	Item  "project\\localpath1\\localpath2"  retrieved resulted in  "Beim Öffnen eines Ordners ist ein Fehler aufgetreten. Beim Lesen ist ein Fehler aufgetreten: error:140E0197:SSL routines:SSL_shutdown:shutdown while in init"
[OCC::ActivityListModel::addErrorToActivityList 	Error successfully added to the notification list:  "Beim Öffnen eines Ordners ist ein Fehler aufgetreten. Beim Lesen ist ein Fehler aufgetreten: error:140E0197:SSL routines:SSL_shutdown:shutdown while in init"
[OCC::SyncJournalDb::close 	Closing DB "X:/Users/User/project/localpath1/localpath2/._sync_31b66fb582b8.db"
[OCC::SyncEngine::finalize 	CSync run took  16922 ms
[OCC::Folder::slotSyncFinished 	Client version 2.6.4stable-Win64 (build 20200303)  Qt 5.12.5  SSL  OpenSSL 1.1.1d  10 Sep 2019
[OCC::Folder::slotSyncFinished 	SyncEngine finished with ERROR
[OCC::Folder::showSyncResultPopup 	Folder sync result:  2
[OCC::Folder::slotSyncFinished 	the last 12 syncs failed
[OCC::ownCloudGui::slotSyncStateChange 	Sync state changed for folder  "https://example.org/owncloud/remote.php/dav/files/user/path1" :  "Error"
[OCC::FolderMan::slotFolderSyncFinished 	<========== Sync finished for folder [projects\localpath1\localpath2] of account [user@example.org] with remote [https://example.org/owncloud/remote.php/dav/files/user/path1]

I have worked around this problem with the Windows Client 2.6.3.

@OlafK: I have the same problem. Have you seen my thread?

Okay, @user9812378 et @eisente. I installed Windows Client 2.6.3. Now NC Client crashed when it started to check for updates for the second and third directory. I tried some times, than I paused synchronisation before the app crashed, removed the sync directories, and added them again.
Now it worked. It downloaded some gigabyte of data and some zero-byte files. This raised a few conflicted files but I was able to sort them out manually in a few minutes.
Now it works: Installing 2.6.3, and re-adding the sync paths.
Thanks for your idea @eisente