How can I check, solve this? and I am using multiple websites/domains on the same droplet. I don;t know if that is a part of the issue.

are all the domains giving you spam issues or just a specific one?

whats the domain associated with the droplet?

I have 2 domains. the hostname of my droplet is pandapixl.nl and thats also the name of the droplet and one of my domains. next to that I have another domain. When sending emails to my gmail account myself with the email accounts on those domains it goes all fine. when the website sends an email it goes to spam folder and to hotmail neither one of them arrives.

You can check your PTR records doing a reverse lookup using this tool

http://mxtoolbox.com/SuperTool.aspx

Also do you have an SSL, I try putting your domain in the browser and it pop ‘The connection is untrusted’ and then when I click trust this site it took me to roundcube login page.

Using the same tool above I check for https and it gave me an error. I’m wondering if this have something to do with your email problems.

fixed the ssl on one domain but I don’t know if it will give problems with others since the hostname is different..

I checked reverse lookup but it points to my hostname as expected.. this is so frustrating.. :o

have you tested the email since you fix the SSL problem?

Yes I did. Unfortunately no change :/ i created a ticket and they checked all possibilities but everything is fine according to digital ocean support. Pff

I suggest you take a look at:

Sender ID Framework SPF Record Wizard :
http://www.microsoft.com/mscorp/safety/content/technologies/senderid/wizard/default.aspx

Check your SSL certificates
https://www.sslcertcheck.com

MS SNDS IP Status
https://postmaster.live.com/snds/index.aspx

ReturnPath Sender Score
https://www.senderscore.org

Cisco SenderBase
http://www.senderbase.org/

and join JMRP
The Junk Mail Reporting Program (JMRP) is a service provided for email senders by Outlook.com. It lets you set up a feedback loop, so you can receive copies of messages Outlook.com users mark as junk.

https://postmaster.live.com/snds/JMRP.aspx

fm I checked and went trough all the websites u gave and applied where necessary as you suggested. The only website I had problems with was the first one to create a SPF record wizard. I filled in everything as I thought it should be.. But I don’t know if its correct. Also one of the domains doesn’t have a nice working SSL certificate but one does How can I make them both use that certificate?

This is what I got
v=spf1 mx ip4:188.226.168.192 ip4:188.226.168.195 mx:seconddomain.nl a:hostname.nl mx:firstdomain(sameashostname).nl -all

I changed the names so it would be clear how its build :) the first domain is also the hostname and the one with valid certificate.