Nextcloud 16 on Nginx 1.17.1 -- "Status: 500 Internal Server Error" & "Something is wrong with your openssl setup" ?

[PGNet Dev]

I run nginx/1.17.1 + PHP 7.4.0-dev on linux/64.  It's an in-production 
setup, with lots of directly hosted, as well as proxied, SSL-secured 
webapps.

I've now installed Nextcloud v16.0.3.  For the moment, directly hosted 
on Nginx, not-yet proxied.

It installs to DB with no errors.  &, The site's accessible hosted on 
Nginx; I can get to the app's login page -- securely.

But when I enter login credentials & submit, I get an nginx/fastcgi

	http fastcgi header: "Status: 500 Internal Server Error"

and in Nextcloud logs,

	"Something is wrong with your openssl setup: error:02001002:system 
library:fopen:No such file or directory,"

I've posted an issue, with config & error details, here:

	https://github.com/nextcloud/server/issues/16378

Since I've got lots of other webapps running securely with no issues, 
and I _am_ able to get to Nextcloud's secure login page with my 
Nginx-served SSL cert, I suspect the problem's in Nextcloud -- NOT nginx.

But thought I'd check-in here ... anyone successfully using Nextcloud on 
Nginx that can suggest what the problem is, or a fix?

OR, *is* this an Nginx issue that I simply haven't recognized ?  Header 
I've missed, or misconfigured?  Not immediately clear to me why it 
wouldn't surface on the login page at 1st connect ...