Yesterday I updated to Magento 2.2.8. Now, I'm having serious issues that I'm not even sure what triggers them.
Firstly, yesterday, I was having issues with the SMTP (Mageplaza SMTP module) - when I try to send test mail, the error
"A technical problem with the server created an error. Try again to continue what you were doing. If the problem persists, try again later."
keeps showing. In trying to resolve the outgoing emails issues I went ahead and enabled "Asynchronous sending" from Sales > Sales Emails.
This did not resolve anything. So I went back to disable it only to find out that I'm unable to. When I choose "disable" and click "Save Config" I get a blank page. When I use the browser back button the setting has not changed.
The same blank page issue I have on the Contact form. When I submit the contact form I get redirected to a blank page at
https://example.com/contact/index/post/
And I receive no messages from the contact form.
Please, help me with these issues. I have no idea what causes them. Is the 2.2.8 version broken? Do I need to fix something else? Any suggestions are welcome. :(