Wouldn't be surprising if they implemented a way for your outgoing emails after the call to not go through.
Companies worldwide who are doing these mass layoffs now are essentially immediately cutting off access to systems after layoff notification, because they are afraid of being put on blast by disgruntled laid-off people.
There has recently been an uptick with people who are fed-up with being treated like dirt at work, who when told they've been laid-off, then pen scathing "farewell" messages to their boss/es, HR, and cc-ing the entire rest of the company's individual employees; saying EXACTLY how they've been mistreated, and by whom.
Naming names and places and things in particular, in a no holds barred, adios/adieu/FU final email doesn't look good for "leadership" and the company as a whole, so the latest trend is for them to try to cut you off at the pass, by not allowing you access to company-wide email almost immediately after they let you know you've been chosen to hit the bricks.
For those who are inclined to write and send such an email, it might behoove them to get it written and saved into a Word doc (complete with "To" recipients' email addys included) which is OFF company systems/devices, then WHEN ON THE LAYOFF CALL, quickly open that doc, copy, then paste its contents into a company email and hit SEND immediately as the call is wrapping up. Don't even wait until the call is finished, hit send right when you're saying, "Goodbye". lol.
Not necessarily recommending this, but it's certainly an option.
Something to think about, and possibly prepare for oneself ahead of time.