Scheduled Upload of graphs and data not working anymore

[Nimbus43]

Hello,
about a week ago my weather station server stopper sending my daily (24hr) weather report as an email to one of my email addresses.
However, the weather data are being sent without any problems to a website in the US.
A hint what could be the cause would be very much appreciated.
At first I suspected my email provider but after I changed the sender's address the problem was not solved.

[Nimbus43]

Hello,
about a week ago my weather station server stopper sending my daily (24hr) weather report as an email to one of my email addresses.
However, the weather data are being sent without any problems to a website in the US.
A hint what could be the cause would be very much appreciated.
At first I suspected my email provider but after I changed the sender's address the problem was not solved.

I checked the error reports and found that the email server does not accept the sender's address, error 554 ...

[Nimbus43]

Apr 27 15:50:06 meteohub-rpi logger: sendmail: server message: 554-Reject due to policy restrictions.
Apr 27 15:50:06 meteohub-rpi logger: sendmail: server message: 554 For explanation visit https://www.ionos.com/help/index.php?id ... 93.28&c=hd
Apr 27 15:50:06 meteohub-rpi logger: sendmail: could not send mail (account default from /home/meteohub/msmtprc)
Apr 27 15:52:06 meteohub-rpi logger: sendmail: the server did not accept the mail
Apr 27 15:52:06 meteohub-rpi logger: sendmail: server message: 554-Transaction failed
Apr 27 15:52:06 meteohub-rpi logger: sendmail: server message: 554-Reject due to policy restrictions.
Apr 27 15:52:06 meteohub-rpi logger: sendmail: server message: 554 For explanation visit https://www.ionos.com/help/index.php?id ... 93.28&c=hd
Apr 27 15:52:06 meteohub-rpi logger: sendmail: could not send mail (account default from /home/meteohub/msmtprc)