I have found the reason of your Email Problems:
If using your support-form and activating "send me copy of request" you send me an email with my own email as Sender. This is not allowed because your mailserver is not authorized to send emails for my Domain. You MUST use your Email as Sender. Thats the reason for the spf error, and the error did correctly occur.
I can recieve all emails wich have the Sender …@devart.com, so I can do like you suggested and hope you send notification About nighty build with your own email as Sender.
[SMTP 000618 11-07-18 10:28:34] EHLO
mail.devart.com
[SMTP 000618 11-07-18 10:28:34] 250-Welcome 5.79.86.80, nice to meet you...
[SMTP 000618 11-07-18 10:28:34] 250-AUTH=PLAIN LOGIN
[SMTP 000618 11-07-18 10:28:34] 250-AUTH PLAIN LOGIN
[SMTP 000618 11-07-18 10:28:34] 250-SIZE
[SMTP 000618 11-07-18 10:28:34] 250-DSN
[SMTP 000618 11-07-18 10:28:34] 250-ETRN
[SMTP 000618 11-07-18 10:28:34] 250-STARTTLS
[SMTP 000618 11-07-18 10:28:34] 250 HELP
[SMTP 000618 11-07-18 10:28:34] STARTTLS
[SMTP 000618 11-07-18 10:28:34] 220 Go ahead
[SSMT 000618 11-07-18 10:28:34] Switching to secure channel. Using Tls12.
[SSMT 000618 11-07-18 10:28:34] EHLO mail.devart.com
[SSMT 000618 11-07-18 10:28:34] 250-Welcome 5.79.86.80, nice to meet you...
[SSMT 000618 11-07-18 10:28:34] 250-AUTH=PLAIN LOGIN
[SSMT 000618 11-07-18 10:28:34] 250-AUTH PLAIN LOGIN
[SSMT 000618 11-07-18 10:28:34] 250-SIZE
[SSMT 000618 11-07-18 10:28:34] 250-DSN
[SSMT 000618 11-07-18 10:28:34] 250-ETRN
[SSMT 000618 11-07-18 10:28:34] 250 HELP
[SSMT 000618 11-07-18 10:28:35]
MAIL FROM:<[email protected]> SIZE=2304
[SSMT 000618 11-07-18 10:28:35] Verifying domain lhsoft.de
[SSMT 000618 11-07-18 10:28:35] Domain is local. Skipping verification.
[SSMT 000618 11-07-18 10:28:35] 250 Sender "
[email protected]" OK...
[SSMT 000618 11-07-18 10:28:35] RCPT TO:<
[email protected]>
[SSMT 000618 11-07-18 10:28:35] User overrides Greylisting. Status is OFF
[SSMT 000618 11-07-18 10:28:35] 250 Local recipient "
[email protected]" OK...
[SSMT 000618 11-07-18 10:28:35] DATA
[SSMT 000618 11-07-18 10:28:35] Checking reverse PTR entry...
[SSMT 000618 11-07-18 10:28:35] Result: mail.devart.com
[SSMT 000618 11-07-18 10:28:35] Checking SPF
[SSMT 000618 11-07-18 10:28:35] TXT Records for lhsoft.de are not in cache
[SSMT 000618 11-07-18 10:28:35] Retrieving TXT records for lhsoft.de using DNS server 178.248.240.4
[SSMT 000618 11-07-18 10:28:35] Registering TXT records with cache
[SSMT 000618 11-07-18 10:28:35] SPF Result: (-) The IP address <ip> is in the not permitted set
[SSMT 000618 11-07-18 10:28:35] Incrementing the counter for IP address 5.79.86.80 in lockout manager: Current=1, Allowed=4
[SSMT 000618 11-07-18 10:28:35] 554 Rejected by SPF: (-) The IP address 5.79.86.80 is in the not permitted set
[SSMT 000618 11-07-18 10:28:35] SMTP connection 000618 on 178.248.246.166:25 with 5.79.86.80:64602 ended
[SSMT 000618 11-07-18 10:28:35] Number of current secure SMTP connections: 0