If you’re receiving the popup message from Google G Suite – Gmail saying, “Oops, something went wrong. Recent changes may not have been saved” don’t freak out – I’ve experienced this too.
This is the message you will receive when you try to compose an email or try to send an email from Gmail. Yes, it’s impacted our business emails.

It appears there are some service issues with Google Suite and you can check the status by going here: G Suite Status Dashboard

If you click on the orange status icon for Gmail, you will see the issue service details.

I’m pretty sure the engineers at Gmail are frantically trying to fix the problem since it’s affecting many business and users – both receiving and sending emails. The best thing you can do right now is to make sure you type your email on Notepad or another text program before you send it in Gmail, as you may lose the email when the popup message shows up.
You may also want to try sending the urgent emails via the mobile app (it may work) as I tested this a few times and the popup message won’t appear.
Good luck and I hope this didn’t impact your business too much.