Your comments

I "deleted" the containers and stated from scratch and everything went smooth the second time for whatever reason.

I tried the example for onlyoffice psoted here and if I visit: https://office.mydomain.tldI get the welcome text but if I visit https://office.mydomain.tld/healthcheck/ I get "false" in the browser and the onlyoffice contaienr lgos saying:

[2021-05-29T13:32:09.587] [ERROR] nodeJS - healthCheck error │
│ error: password authentication failed for user "onlyoffice" │
│ at Connection.parseE (/snapshot/server/build/server/DocService/node_modules/pg/lib/connection.js:614:13) │
│ at Connection.parseMessage (/snapshot/server/build/server/DocService/node_modules/pg/lib/connection.js:413:19) │
│ at Socket. (/snapshot/server/build/server/DocService/node_modules/pg/lib/connection.js:129:22) │
│ at Socket.emit (events.js:198:13) │
│ at addChunk (_stream_readable.js:288:12) │
│ at readableAddChunk (_stream_readable.js:269:11) │
│ at Socket.Readable.push (_stream_readable.js:224:10) │
│ at TCP.onStreamRead [as onread] (internal/stream_base_commons.js:94:17)

Any ideas? Google didn't help :-/

Thanks, I sorted it out, just created a new user and used that user/group instead of root.

OK, thanks for your reply, I wasn't aware I shouldn't mention other products, sorry about that and thanks for clarifying. 

Still, any chance of a reply to this question:

can filerun be accesses like a drive? I am not sure how to best describe it, say kinda mount it with fuse or something?

oh, I should have read that properly, sorry for the confusion

I am having the exact same problem when trying to open a file with my locally installed Office product: 

We can't connect to "https://yourserver.com:4430/filerun/wl/rw/jhhWHWghWYWYUuyWYUW56GwerPOSP01/test.docx'. Please make sure you're using the correct web address

I am using filerun via docker - does this mean that there is no mod_rewrite solution built into the docker image?

It seems there is now an option to use a local LibreOffice but I am wondering how I can do this if I am using filerun via Docker?

Could you give some pointers please? Simply selecting user root and uid 0 leads to this error:

+ exec apache2-foreground │
│ AH00526: Syntax error on line 115 of /etc/apache2/apache2.conf: │
│ Error:\tApache has not been designed to serve pages while\n\trunning as root. There are known race conditions that\n\twill allow any local user │
│ to read any file on the system.\n\tIf you still desire to serve pages as root then\n\tadd -DBIG_SECURITY_HOLE to the CFLAGS env variable\n\tand t │
│ hen rebuild the server.\n\tIt is strongly suggested that you instead modify the User\n\tdirective in your httpd.conf file to list a non-root\n\tu │
│ ser.\n

The reason I am asking, maybe there is an easier way for what I need. I need to give access permissions to filerun to some folder mounted via volumes from outside and those are ownd by root:root - so basically, inside the docker container the web server needs to run with uid 0 and guid 0 or at least one of them as I understand things.

Sorry to revive this old thread but can you please clarify the correct credentials?

https://docs.filerun.com/updating says: 

Access your FileRun installation and log in as superuser (The default login name of the superuser is “admin”).

https://docs.filerun.com/docker says:

The default FileRun credentials are as follows:

* Username: superuser

* Password: superuser