Hi @Rahim Molvani,
Thank you for posting in this community.
Since we can't reproduce your situation, we need to narrow down the problem and try some things. So, please kindly provide more information below to let us work further.
1.It looks like you have to enable TLS1.2 in your .net configuration. Please refer this article to configure: Enable TLS 1.1 and TLS 1.2 onwards support in Office Online Server. Once the configuration is complete, please restart Office Online Server and see if the problem persists.
2.Is it possible to create new Office documents properly in SharePoint Server 2019? You can also try creating new files under OneDrive under other accounts. We need to confirm if this issue is only under OneDrive and if it is only in OneDrive for individual users?
3.You can try using Internet Explorer to see if the problem persists.
4.If you can't even create new files in SharePoint Server 2019 then the problem is most likely with your installation of Office Online Server or configuration of Office Online Server for SharePoint Server 2019.
You can start by disconnecting SharePoint from Office Online Server. (Also applies to SharePoint 2019.)
Then re-deploy Office Online Server and re-configure Office Online Server for SharePoint Server (Also applies to SharePoint 2019.)
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