btcpayserver: [Bug]: Crash when accessing /register endpoint after a fresh install on Ubuntu

What is your BTCPay version?

Running v1.7.3

How did you deploy BTCPay Server?

I have followed the Extended Manual Setup guide to install on Ubuntu. All the steps seemingly succeeded.

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.4 LTS
Release:        20.04
Codename:       focal

What happened?

Once the server is up and running (syslog does not show any errors) I try to GET the main page, get redirected to /register and when the browser requests /register the server crashes.

Logs attached below (trimmed because the stack dump is huge).

How did you encounter this bug?

See above.

Relevant log output

Jan 01 18:11:52 btcnode run.sh[55888]: info: Configuration:  Data Directory: /home/bitcoin/.btcpayserver/Main
Jan 01 18:11:52 btcnode run.sh[55888]: info: Configuration:  Configuration File: /etc/btcpay/btcpay.config
Jan 01 18:11:53 btcnode run.sh[55888]: info: BTCPayServer.Plugins.PluginManager: Loading plugins from /home/bitcoin/.btcpayserver/Plugins
Jan 01 18:11:53 btcnode run.sh[55888]: info: BTCPayServer.Plugins.PluginManager: Adding and executing plugin BTCPayServer - 1.7.3.0
Jan 01 18:11:53 btcnode run.sh[55888]: info: BTCPayServer.Plugins.PluginManager: Adding and executing plugin BTCPayServer.Plugins.Shopify - 1.7.3.0
Jan 01 18:11:53 btcnode run.sh[55888]: info: BTCPayServer.Plugins.PluginManager: Adding and executing plugin BTCPayServer.Plugins.Crowdfund - 1.7.3.0
Jan 01 18:11:53 btcnode run.sh[55888]: info: BTCPayServer.Plugins.PluginManager: Adding and executing plugin BTCPayServer.Plugins.PayButton - 1.7.3.0
Jan 01 18:11:53 btcnode run.sh[55888]: info: BTCPayServer.Plugins.PluginManager: Adding and executing plugin BTCPayServer.Plugins.PointOfSale - 1.7.3.0
Jan 01 18:11:53 btcnode run.sh[55888]: info: BTCPayServer.Plugins.PluginManager: Adding and executing plugin BTCPayServer.Plugins.Custodians.Fake - 1.0.0.0
Jan 01 18:11:53 btcnode run.sh[55888]: info: Configuration:  Supported chains: BTC
Jan 01 18:11:53 btcnode run.sh[55888]: info: Configuration:  BTC: Explorer url is http://127.0.0.1:24444/
Jan 01 18:11:53 btcnode run.sh[55888]: info: Configuration:  BTC: Cookie file is /home/bitcoin/.nbxplorer/Main/.cookie
Jan 01 18:11:53 btcnode run.sh[55888]: info: Configuration:  Network: Mainnet
Jan 01 18:11:55 btcnode run.sh[55888]: info: Configuration:  Root Path: /
Jan 01 18:11:56 btcnode run.sh[55888]: info: Configuration:  Connection to NBXplorer's database successful, dashboard and reporting features activated.
Jan 01 18:11:56 btcnode run.sh[55888]: info: PayServer:      Starting listening NBXplorer (BTC)
Jan 01 18:11:56 btcnode run.sh[55888]: info: PayServer:      Start watching invoices
Jan 01 18:11:56 btcnode run.sh[55888]: info: PayServer:      Starting payment request expiration watcher
Jan 01 18:11:56 btcnode run.sh[55888]: info: PayServer:      BTC: Checking if any pending invoice got paid while offline...
Jan 01 18:11:56 btcnode run.sh[55888]: info: PayServer:      0 pending payment requests being checked since last run
Jan 01 18:11:56 btcnode run.sh[55888]: info: Configuration:  Now listening on: http://127.0.0.1:23000
Jan 01 18:11:56 btcnode run.sh[55888]: info: PayServer:      BTC: 0 payments happened while offline
Jan 01 18:11:56 btcnode run.sh[55888]: info: PayServer:      Connected to WebSocket of NBXplorer (BTC)
Jan 01 18:12:36 btcnode run.sh[55888]: fail: Microsoft.AspNetCore.Server.Kestrel: Connection id "0HMNC2BNDTR2R", Request id "0HMNC2BNDTR2R:00000002": An unhandled exception was thrown by th
e application.
Jan 01 18:12:36 btcnode run.sh[55888]: System.InvalidOperationException: Cannot find compilation library location for package 'System.Security.Cryptography.Pkcs'
Jan 01 18:12:36 btcnode run.sh[55888]:    at Microsoft.Extensions.DependencyModel.CompilationLibrary.ResolveReferencePaths(ICompilationAssemblyResolver resolver, List`1 assemblies)
Jan 01 18:12:36 btcnode run.sh[55888]:    at Microsoft.Extensions.DependencyModel.CompilationLibrary.ResolveReferencePaths()
Jan 01 18:12:36 btcnode run.sh[55888]:    at Microsoft.AspNetCore.Mvc.ApplicationParts.AssemblyPartExtensions.<>c.<GetReferencePaths>b__0_0(CompilationLibrary library)
Jan 01 18:12:36 btcnode run.sh[55888]:    at System.Linq.Enumerable.SelectManySingleSelectorIterator`2.MoveNext()

What browser do you use?

Happens with curl, safari, chrome…

Additional information

Possibly related to https://github.com/btcpayserver/btcpayserver/pull/4113 or to https://github.com/btcpayserver/btcpayserver/issues/3258

Are you sure this is a bug report?

• I confirm this is a bug report