Hi,
Am having exactly the same issue, everything else seems to be working well.
Version 3.8.6.13 php Version 7.4 as anything lower has been depreciated on own server. Using SMTP. Config is correct as I am receiving emails. Have tried multiple browsers, still no fix.
Error Message: Unexpected Token
Had Feng a good while back on self hosted, and never had this problem. Am sure it'll be a code issue somewhere, so fixable, if someone can allude to a fix?
NB: Am getting email address bar with Bcc and CC. Note that when email write discarded, even when unable to add text, getting the following - {"contents":{},"current":{"type":"back","data":null,"actions":null,"config":null,"makeDefault":null},"errorCode":0,"errorMessage":"","u":2,"scripts":["https:\/\/****.****.**\/public\/assets\/javascript\/og\/modules\/addMessageForm.js?rev=1","plugins\/mail\/public\/assets\/javascript\/AddMail.js?rev=1"],"events":[]}