Comment by tromp

Same here on MacOS Catalina 10.15.7. The original invocation runs fine

    $ bash -c './redbean.com -vv'
    W2021-02-26T01:50:12.665277:tool/net/redbean.c:1144:redbean:3302] setsockopt(server, IPPROTO_TCP, TCP_FASTOPEN, &yes, sizeof(yes)) → EINVAL/err=22/errno:22/GetLastError:0
    W--------------------000015:tool/net/redbean.c:1145:redbean:3302] setsockopt(server, IPPROTO_TCP, TCP_QUICKACK, &yes, sizeof(yes)) → ENOPROTOOPT/err=42/errno:42/GetLastError:0
    V--------------------000022:tool/net/redbean.c:1166:redbean:3302] 0.0.0.0:8080 listen

Visiting http://127.0.0.1:8080/ in my web browser shows a nice redbean page with lobster graphic at http://127.0.0.1:8080/tool/net/redbean.html but then following usage instructions in another shell:

    $ echo '<b>hello</b>' >index.html
    $ zip redbean.com index.html
      adding: index.html (stored 0%)
    $ ./redbean.com -vv
    Killed: 9

I blame my zip

    $ zip -v
    Copyright (c) 1990-2008 Info-ZIP - Type 'zip "-L"' for software license.
    This is Zip 3.0 (July 5th 2008), by Info-ZIP.
    Currently maintained by E. Gordon.

Addition of index.html shrinks(!) redbean.com from size 204800 to size 204348, with changes starting from char 172938. That clearly corrupts the portable executable format.