Issue sending email for password recovery

I have been testing the ability to send users an email to recover lost password and its not working
system: Ubuntu 18.04

I get this message
« unable to verify the first certificate »

error[10/2/2021, 7:16:08 PM] Error in email sender.

« err »: {
« stack »: « Error: unable to verify the first certificate\n at TLSSocket.onConnectSecure (_tls_wrap.js:1502:34)\n at TLSSocket.emit (events.js:314:20)\n at TLSSocket.EventEmitter.emit (domain.js:483:12)\n at TLSSocket._finishInit (_tls_wrap.js:937:8)\n at TLSWrap.ssl.onhandshakedone (_tls_wrap.js:711:12) »,
« message »: « unable to verify the first certificate »,
« code »: « ESOCKET »,
« command »: « CONN »

Thanks for any help


I guess that the problem comes from the expiration of the old Let Encrypt root certificate.
Please, have a look at Old Let’s Encrypt Root Certificate Expiration and OpenSSL 1.0.2 - OpenSSL Blog and try the proposed workarounds.