My company uses Google for email, which implies the use of the exact same authentication mechanism used by free Gmail accounts - at least in my case. K-9 Mail knows how to handle @gmail.com accounts and starts the correct authentication flow for them, but it is only for accounts in the gmail.com domain. Of course my company email domain is mycompany.com, not gmail.com. In this scenario, it is not possible to trigger the Gmail authentication flow, so I cannot register my company email account in K-9. I tried the manual configuration, but didn’t work. I wonder if there is a way to tell K-9 that the account is backed by Google so the correct authentication flow is used.
Are you sure your IT department has enabled third party email applications in the Google Workspace console or whatever it’s called? Most don’t permit use of K-9 or Thunderbird, as the email is no longer manageable.
You’ve set the server as imap.gmail.com for incoming and smtp.gmail.com for outgoing? What’s the Authentication type? Try “OAuth 2.0”, although as I mentioned, your IT group may prevent this from working.
If a company is using Google’s servers for incoming mail directly (MX record), K-9 Mail should be able to find the server settings automatically. In your case the company might be using some intermediate MX (e.g. for malware detection). In that case you have to manually set up the account. See How do I add a Google Workspace account?
Note: There’s currently an ongoing issue with OAuth (sometimes) being blocked by Google for K-9 Mail. See Yet another issue with Gmail