sorry for my bad english

i have problems with the new myvesta installation. I installed myvesta on three different servers with the same hardware. With two servers everything works fine but with one I can't send any emails. I compared everything (exim.conf etc.) between sever one (where everything is running) and server two (where sending email is not possible) and found no difference. All confs are equal 1: 1. Each of the three servers has its own fixed IP and domain. I have no idea what's wrong with some of them. Can anyone help me here? Thank you
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<<>> DiG 9.11.5-P4-5.1+deb10u2-Debian <<>> xxxxxl.eu mx
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 45398
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;axxxxxx.eu. IN MX
;; ANSWER SECTION:
xxxxxxxl.eu. 59 IN MX 10 xxxx.eu.
;; Query time: 44 msec
;; SERVER: 192.168.0.1#53(192.168.0.1)
;; WHEN: Tue Oct 13 08:50:22 CEST 2020
;; MSG SIZE rcvd: 56
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telnet x.x.x.x 25
Trying x.x.x.x.13...
Connected to x.x.x.x.
Escape character is '^]'.
220 xxxx.eu ESMTP Exim 4.92 Tue, 13 Oct 2020 08:22:06 +0200
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My server:
Debian 10.6 whit fresh myvesta
Apache2 - yes
Ngnix -no ( only for vesta panel at 8083)
Exim4 -yes
Dovecot -yes
Bind9 - yes
Clamav - daemon - no
Spassamasin - yes
iptables - yes
fail2ban - yes
mysql - yes
proftpd - yes