chkservd reports exim as down

Hi guys, today chkservd started reporting that exim is down, when it's not. Here's the log ; TCP Transaction Log: << 220-cpanel.domain.com ESMTP Exim 4.91 #1 Wed, 17 Apr 2019 10:25:16 +0200 << 220-We do not authorize the use of this system to transport unsolicited, << 220 and/or bulk e-mail. >> EHLO localhost << 250-cpanel.domain.com Hello localhost [127.0.0.1] << 250-SIZE 52428800 << 250-8BITMIME << 250-PIPELINING << 250-STARTTLS << 250 HELP >> AUTH PLAIN somerandomstringhere << 503 AUTH command used when not advertised exim: ** [503 AUTH command used when not advertised != 2] : Died
I'm not sure what exactly happened, but SMTP via port 25 is not working. TLS on 587 is working fine. The only option in exim I could think of to be related to this issue is ; "Require clients to connect with SSL or issue the STARTTLS command before they are allowed to authenticate with the server. [?] ON " which is ON by default. I turned this off and on last night in order to test something, but it's left at where it was. Also " Allow Plaintext Authentication (from remote clients) " is set to ON. Can someone point me in the right direction here? Thanks.