Happy to help you. I moved this thread to the suitable section.
First, I like to point you to our help article about mail issues: Common questions about emails - Sitejet Help
Second, the SPF record should definitely also read: v=spf1 a:mx1.sitehub.io a:mx2.sitehub.io mx -all
if you like to send mails via Sitejet. One of the reasons is described here: 🔷 Security issue | Emails to Gmail not deliverable - Adjust SPF-Record
However, your issue seems to be with you being blocked due to various reasons. First, I would like you to sign out of all mailboxes you are using the mail address with. Then, log in and change the password for that mail address. Once that is done, the mail address should not be blocked by the system anymore.
Do a test run. Does the mail work again? If yes, fine. Go and add the new password again to one tool at a time and see if you are blocked again.
The reason for this is that the system is blocking you when there is too many log ins at a time. At some point the system regards this as a security issue.
Please keep me on the loop here if that solved the issue. 