[tex4ht] make4ht-lib: Fatal error. Command t4ht returned exit code 1, Too many characters (> 500) for map line: `l'

[Nasser M. Abbasi]

I am trying to compile the weekly mathematica newsletter I get.
This time, I must have added something that tex4ht does not like
from the email I got from stackexchange.

When I compile the file using the same command I use all the time,
now it gives

===============================
Output written on content_all.dvi (988 pages, 7920264 bytes).
Transcript written on content_all.log.
[INFO]    make4ht-lib: executing: tex4ht  -cunihtf "content_all.dvi"
--- warning --- Too many characters (> 500) for map line: `l'
Then later it gives
........
] [986 file cose265.htm
] [987] [988]
Execute script `content_all.lg'

[INFO]    make4ht-lib: executing: t4ht  -utf8 "content_all.dvi"
--- error ---

t4ht.c (2018-07-04-14:25 kpathsea)
t4ht -utf8
   content_all.dvi

[FATAL]   make4ht-lib: Fatal error. Command t4ht returned exit code 1

================================================

This file (called content_all.tex) compiles with no problem using
lualatex. (with the normal warnings, etc...)

Since tex4ht does not say where the line it is not happy with,
and what exactly is wrong. I am not sure why it giving this error
now.

The command I used is

make4ht --shell-escape -ulm default -a debug -e ./new.mk4
       -c ./nma_mathjax.cfg content_all.tex
       "mathjax,htm,fn-in,3,notoc*,p-width,charset=utf-8"  " -cunihtf -utf8"

Could someone please see if they can reproduce this error?

I put zip file with all the content needed to compile it. After unzipping
the file, it will create folder called content_all/

Issuing the above command inside this folder will show the error.
The above command is also given in a text file inside the folder
called command.tex

Here is the zip file on my site:

https://www.12000.org/tmp/02042021/content_all.zip

Using TL 2020 on Ubuntu.

>which tex4ht
/usr/local/texlive/2020/bin/x86_64-linux/tex4ht

>make4ht --version
make4ht version v0.3f

ps. last week news letter compiled OK. Here is the result

https://www.12000.org/my_notes/mathematica_stackexchange_letters/content_all/content_all.htm

So it is something in this week content which made tex4ht starts giving
errors. May be capacity issue?

Thanks for any suggestions
--Nasser