I have two websites (both mine) https://site1.com and https://site2.com

I created a user for site1.com "benz" password "x". he has readWrite on "db" database.

next on site2.com I put this node.js code and run it via the terminal:

require('mongodb').MongoClient.connect(
'mongodb://benz:xxxx@site1.com:27017/db?ssl=true&authMechanism=SCRAM-SHA-1&authSource=db'
, {server:{
sslValidate:true
, checkServerIdentity:true
, sslCA:[require('fs').readFileSync('/etc/letsencrypt/lets-encrypt-x3-cross-signed.pem')]
, sslKey:require('fs').readFileSync('/etc/letsencrypt/live/site2.com/privkey.pem')
, sslCert:require('fs').readFileSync('/etc/letsencrypt/live/site2.com/fullchain.pem')
}}
, function(e,db)

);

I get

null

/var/sentora/hostdata/zadmin/node_modules/mongodb/lib/server.js:235
process.nextTick(function()

)

I turn both firewalls off and I get the same error!

If I deliberately change my sslCert from `fullchain.pem` to `chain.pem` (another file that does exist) then I get a separate error

Error: error:0B080074:x509 certificate routines:X509_check_private_key:key values mismatch
at Error (native)
at Object.createSecureContext (_tls_common.js:87:19)
at Object.exports.connect (_tls_wrap.js:971:21)
at Connection.connect (/var/sentora/hostdata/zadmin/node_modules/mongodb/node_modules/mongodb-core/lib/connection/connection.js:348:27)
at Immediate._onImmediate (/var/sentora/hostdata/zadmin/node_modules/mongodb/node_modules/mongodb-core/lib/connection/pool.js:187:20)
at processImmediate [as _immediateCallback] (timers.js:383:17)

Which seems to show that the certs are fine but the auth is not fine

I have run out of ideas