Testing v1.6.0 RC1 on NC20.02 RC: Can not add date option

[brtptrs]

What is going wrong?

Describe the bug
Testing v1.6.0 RC1 on NC20.02 RC: I can not add a date option to a new poll.

To Reproduce
Steps to reproduce the behavior:

1. Create a new date poll
2. Select a date+time
3. Click "ok"

Expected behavior
Date option should be saved and allow to add one more

Information about your polls installation

V1.6.0 RC1

Fresh installation or update from a prior version (from which one)?
Upgrade from previous

How did you install this version?(Appstore or describe installation)
Download from Github and unzip in app folder
Install from gui. No errors shown

Information about your Instance of Nextcloud

Nextcloud version: NC20.02 RC

Firefox throws a js error:
"Uncaught (in promise) Error: Request failed with status code 500"

[dartcafe]

Do you have additionally information from the server log?

[brtptrs]

We are seeing a server error (500), apparently resulting from a db error.

error_polls_2020_11_16.txt

[dartcafe]

If you are able to change db properties, make sure that the fields preferences and user_id of the table oc_polls_preferences have a default = '' configured.

I will check the migration.

[dartcafe]

But I am confused. This should not be connected to date polls. This is a general error, which may occur on many situations.

[brtptrs]

Setting the db properties solves the problem for me.
Thank you!

Regarding the "date poll" question. I have not tested text polls. That was just mentioned to state that I've only tested date polls.