Emails sent from thunderbird arrive at spam, arrive fine sent from web host email.
I use 1and1 hosting for a business website and company email provider. When I send emails to gmail accounts using the 1and1 interface they arrive just fine but when I send them using thunderbird they arrive at the spam folder.
I have confirmed this by sending to several different gmail addresses and from the several company accounts I use in thunderbird. The same thing always happen, the emails sent to gmail through thunderbird are sent to spam but those sent directly from 1and1 arrive perfectly.
Is there some setting in thunderbird that is causing this problem? I have tried turing on and off anti spam and antivirus setting in the email provider 1and1 but to little effect. Thank you in advance.
Chosen solution
When you send via webmail it is directly going from 1&1 webmail server. When you send via thunderbird it is going via smtp server.
It is possible that gmail is flagging your IP address as one that sends spam. Try changing your IP address to test.
The SMTP server associated with the host of your domain, it is possible that your host's IP (or IP range) may be on one or more blacklist of known spam servers, based on other users of the same service. A web search for email server blacklist will give you several sites you can use to see if your server is on common blacklists.
Sending via webmail could go through completely different servers with different IP numbers explaining why those emails are not being flagged as spam.
Select email so it shows in Message pane. click on 'More' and select 'View source'. In the headers of received messages which have been classified as spam, you may find spam header information added by the mail scanner that classified the message as spam, which might help to work out what is marking it as spam.
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Chosen Solution
When you send via webmail it is directly going from 1&1 webmail server. When you send via thunderbird it is going via smtp server.
It is possible that gmail is flagging your IP address as one that sends spam. Try changing your IP address to test.
The SMTP server associated with the host of your domain, it is possible that your host's IP (or IP range) may be on one or more blacklist of known spam servers, based on other users of the same service. A web search for email server blacklist will give you several sites you can use to see if your server is on common blacklists.
Sending via webmail could go through completely different servers with different IP numbers explaining why those emails are not being flagged as spam.
Select email so it shows in Message pane. click on 'More' and select 'View source'. In the headers of received messages which have been classified as spam, you may find spam header information added by the mail scanner that classified the message as spam, which might help to work out what is marking it as spam.