Why is not possible to use a symlink folder for the custom SSL?

[BobWs]

Hi,
I'm trying to add a symlinked folder to NPM's custom_ssl /volume1/docker/npm/int/data/custom_ssl/npm-1 where is npm-1 is a symlinked folder to a centrale LE SSL folder with the apporiate SSL files fullchain.pem and privkey.pem in it, but when I start the container then I'm getting this error:

❯ Starting nginx ...
nginx: [emerg] cannot load certificate "/data/custom_ssl/npm-1/fullchain.pem": BIO_new_file() failed (SSL: error:02001002:system library:fopen:No such file or directory:fopen('/data/custom_ssl/npm-1/fullchain.pem','r') error:2006D080:BIO routines:BIO_new_file:no such file)
❯ Starting nginx ...
nginx: [emerg] cannot load certificate "/data/custom_ssl/npm-1/fullchain.pem": BIO_new_file() failed (SSL: error:02001002:system library:fopen:No such file or directory:fopen('/data/custom_ssl/npm-1/fullchain.pem','r') error:2006D080:BIO routines:BIO_new_file:no such file)
❯ Starting nginx ...
nginx: [emerg] cannot load certificate "/data/custom_ssl/npm-1/fullchain.pem": BIO_new_file() failed (SSL: error:02001002:system library:fopen:No such file or directory:fopen('/data/custom_ssl/npm-1/fullchain.pem','r') error:2006D080:BIO routines:BIO_new_file:no such file)
❯ Starting nginx ...
nginx: [emerg] cannot load certificate "/data/custom_ssl/npm-1/fullchain.pem": BIO_new_file() failed (SSL: error:02001002:system library:fopen:No such file or directory:fopen('/data/custom_ssl/npm-1/fullchain.pem','r') error:2006D080:BIO routines:BIO_new_file:no such file)

When I remove the symlinked folder a go back to the default ../custom/npm-1/ folder the container starts normal.

How can I use a symlinked folder to the centrale LE SSL folder, So I don't have copy the renewed Certs everytime into the npm-1 folder.
I'm using linuxserver.io/swag for my LE Certs.
TIA