I can't send E-Mails

[LOGODERKING]

Impacted versions

• OS Type: Debian
• OS Version: 12
• Database Type: MySQL
• Database version: 15.1
• Modoboa: 2.2.3
• installer used: Yes
• Webserver: Nginx

Steps to reproduce

Send an Email over the Webmail and press "send" to get the error

Current behavior

It's not sending an email and I keep getting this error:

Failed to load resource: the server responded with a status of 500 ()

Uncaught SyntaxError: Unexpected token '<', "<!DOCTYPE "... is not valid JSON
    at JSON.parse (<anonymous>)
    at Function.parseJSON (jquery.min.js:3:4322)
    at Webmail.<anonymous> (webmail.js:1063:26)
    at Object.i (jquery.min.js:3:6336)
    at c (jquery.min.js:3:7857)
    at Object.fireWith [as rejectWith] (jquery.min.js:3:8658)
    at k (jquery.min.js:5:14040)
    at XMLHttpRequest.r (jquery.min.js:5:18226)

Expected behavior

Normally it should just send the email

Video/Screenshot link (optional)