Owncloud Client Mac does not save password


my owncloud desktop client does not save the credentials/the password properly. Owncloud (i.e. the keychain access) has a value stored, which does not work, also, if I re-enter the password correct, it does not login. I also reset the apple keychain access (which generates a new one and copies the old file in an archive), where the owncloud password is stored, but it did not help.
I looked at the keychain access while trying to login into Owncloud after a restart, and owncloud client is generating a new keychain access entries for every owncloud start/login attempt - for clientkeyPEM, for clientCertificatePEM and for the password itself.

I do not know at all, where to go on searching for a mistake. Would appreciate any hint, since I am also new to Mac OS X.

Steps to reproduce
1. Start Owncloud
2. Set up an owncloud account which is working (sync works well)
3. Close Owncloud
4. Start Owncloud
5. OC Client Asking for Password.
6. Using pre-stored password from keychain access does not work, manual enter of password neither (entered via copy and paste, password tested with access).
7. Owncloud is not connected, not able to sync
8. To make Owncloud work again, it is necessary to delete the account and set it up again. Then it is working, until owncloud client is closed and restarted, there it starts with 4.

Expected behaviour
Owncloud desktop file client should login with the stored credentials/password.

Actual behaviour
Owncloud desktop client does not login.

Client configuration
Client version: 2.3.1 build 4139
Client operating system: Mac OS X Sierra 10.12.4

Server configuration
Operating system: not sure
Web server: see above
Database: see above
PHP version: see above
ownCloud version (see ownCloud admin page): 9.1.4
Updated from an older ownCloud or fresh install:
Special configurations (external storage, external authentication, reverse proxy, server-side-encryption):

ownCloud log (data/owncloud.log)

Please paste possible errors in the following code block, see https://central.owncloud.org/t/how-to-find-webserver-or-oc-logfile-enable-php-logfile/808 for more info

Your best bet with such issues is mostly to either search the issue tracker of the sync client to find issues like https://github.com/owncloud/client/issues/5280 or to report a new issue there.

Thanks for the link, I will give it a try!

Linking https://github.com/owncloud/client/issues/5750