Can receive emails but not send?

 One of our club members (Club #9196) is able to receive emails from FreeToastHost, but when they send emails to members, the messages don't go through. The issue appears to involve their email account with @centurylink.org. When examining the email headers, I noticed that the "mailed-by" field is showing as centurylink.net, while the "signed by" field displays "mail2world.com."There are no bounce-back messages indicating a bad address, which makes it difficult to troubleshoot.any insight would be appreciated.
 

We will need a first name or email address so we can investigate.
Most probably the email is associated with a spammer email host and is blocked.

Hi Brian,
jane.m@centurylink.net
This member can receive but can't send.emails.
Club 9196.
Thanks
Leo

She hosts her email with a company that allows spammers and one of the multitude of IP addresses they use is probably blocked.
If she can provide the internet headers of the bounced emails it will give us a better chance of finding the block.

from: jane.m <jane.m@centurylink.net>
to: Leo Smith <leo.w.smith@gmail.com>
date: Oct 19, 2024, 8:12 AM
subject: Re: Freetoast
mailed-by: centurylink.net
signed-by: mail2world.com
security: mail2world.com did not encrypt this message Learn more
: Important because previous messages in the conversation were important.

She doesn't get emails bounced back to her.

That is not an email header from her to a FTH email address.
Exactly what email address is she attempting to send to?