still i am facing below issue. Please help me.
I already disable gmail features

code: 'EAUTH',
response: '535-5.7.8 Username and Password not accepted. Learn more at\n' +
'535 5.7.8 https://support.google.com/mail/?p=BadCredentials i5sm8565805wrv.34 - gsmtp',
responseCode: 535,
command: 'AUTH PLAIN'

after doing what instructed my email fails to send and returns this error.

TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string. Received undefined
at validateString (internal/validators.js:120:11)
at Object.resolve (path.js:980:7)
at ExpressHandlebars._resolveLayoutPath (/home/marvic/Documents/email_schedule/node_modules/nodemailer-handlebars/node_modules/express-handlebars/lib/express-handlebars.js:342:17)
at ExpressHandlebars. (/home/marvic/Documents/email_schedule/node_modules/nodemailer-handlebars/node_modules/express-handlebars/lib/express-handlebars.js:223:35) {
code: 'ERR_INVALID_ARG_TYPE'

am i doing something wrong???

ERROR: Error: unable to get local issuer certificate
at TLSSocket.onConnectSecure (node:_tls_wrap:1530:34)
at TLSSocket.emit (node:events:394:28)
at TLSSocket._finishInit (node:_tls_wrap:944:8)
at TLSWrap.ssl.onhandshakedone (node:_tls_wrap:725:12) {
code: 'UNABLE_TO_GET_ISSUER_CERT_LOCALLY'

I even copied and pasted exact code but I get same error:

jquery-3.3.1.min.js:2 POST http://localhost:3000/email 404 (Not Found)

Since I log the ajax requests on console, I also get this:
jquery-3.3.1.min.js:2 XHR failed loading: POST

I tested jquery with different commands and jquery is working fine.
I thought issue might be because of parsing data, so I installed body-parser module didnt help.
Since I saw the ajax error, I was suspecting cross origin policy error. So I added some code to circumvent cross origin policy, I got this error:

:3000/email:1 Failed to load resource: the server responded with a status of 404 (Not Found)

I used the sendFormEmail logic and tried to send an email but it did not work. My changes are

• added name section before email section
• removed .env file entirely and require('dotenv').config(); . I did the same with your code and it worked perfectly.

Link to my repository. Check About folder for js files.