Roundcube

For the past few days I have been getting this pop-up message everytime I try to send an e-mail from my website's e-mail account. What does it mean?

Over the last few days we have been able to log into our homestead email account but after a few minutes receive an error that appears to be from Norton antivirus that the website has been identified as a phishing site and then the computer reboots. What could be causing this?

Is there currently an email problem? Our domain is larrystinsonplumbing.com

When I log in to my account, I get this error. I also tried registering a new account but it still doesn't change anything.

I have always had problems with my clients not receiving my emails. Finally one of my clients sent me a report of why my email ended up in their quarantine folder. The report showed IP address, Location, recipient, inbound, message ID, Etc. But it also has stuff I don't understand: DMARC: 

Here are instructions on how you can check your email once you have created an email address @ your domain name. There are 2 methods to check your Homestead email.First, if you are already logged into the Homestead account, click on "Email" from the tab on the leftChoose the domain you want to check

If you want to export your contacts from Roundcube and convert them into a .csv file to upload to another email client such as outlook here are the steps to do so. Log into your Roundcube account and select contacts from the top right. Once you've selected contacts next select export.You will see

To export contacts from your address book in Roundcube: Log into your Roundcube email.Click on Contacts in the top right cornerClick on "Export" to export all contacts. It will download as a .vcf file. If you only want to export specific contacts, select those contacts and click on the down arr