Neomail accounts not working

All domains on my server have started showing the same error when trying to read webmail in Neomail. All are using the same theme - monsoon. When choosing "Manage Accounts" and then choosing "Read Webmail" for one of the added accounts, I get a 404 - this is the URL showing in the browser: (domain name changed)

Server is running:
WHM 9.3.0 cPanel 9.3.0-R104
RedHat 7.3 - WHM X v3.1.0

"Apache Core" is 1.3.31

Should I:
1 - update cPanel?
2 - update Apache?
3 - do something else

 

Last night's update took me to:
WHM 9.4.0 cPanel 9.4.0-R21
RedHat 7.3 - WHM X v3.1.0

Still no solution to the Neomail issue though. Anyone with a clue?

 

I'm getting a 404, but the URL in the browser is:

...where [IP] is the IP of my server
---username is my username
---domain.com is the domain

When I do: locate /frontend/monsoon/mail/
I get:

/usr/local/cpanel/base/frontend/monsoon/mail/webmailform.html

So 'webmailform.html' seems to be in the right place. I just don't get why this doesn't work. Ideas?

 

...bump...

 

I'm back to report that "cpdan" had the right idea. Although I followed his instructions and thought that I found webmailform.html in the monsoon theme, I misread the screen and it wasn't there. I went back to look at the files, and sure enough, it was missing from a few themes. I've copied it to those where it was missing and all seems to work just fine.

I guess I learned a lesson: check, and check again.

 

Well, it happened again. I'm using the monsoon theme and all was working yesterday, but last night, added email accounts stopped working with a 404 on "webmailform.html ."

Sure enough, that file was missing in /frontend/monsoon/mail/. I put it back and all is working again. I've had "install and keep updated" checked for that theme but now I've removed it in hopes that the file will be left alone. Anyone with a clue why this file would be deleted?

Current system - and has been the same for some days:

WHM 9.4.0 cPanel 9.4.1-R55
RedHat 7.3 - WHM X v3.1.0