So suddenly I realised I have been stopping to receive email in my Gmail Google Apps account. I am able to send email out but not receive it. My DNS and MX records have not been changed and they are still correct and it is working. I have tested and I have not received email for two days now. Is there anything that I can do about it? I am not a paying customer. I am using the legacy Google Apps and not the new G Suite.
Please note that G Suite is simply the renaming of Google Apps. Google Apps and G Suite are one in the same. G Suite support will only assist paid accounts in actively troubleshooting issues. Through G Suite, all free edition accounts are referred to their forums or troubleshooting articles.
There are many potential reasons to stop receiving email. One of the most common issues is that the mailbox account could be full. According to Google however, if the account were full, you would be unable to send email as well. I still recommend checking to ensure that your mailbox is not full. The free edition of Google Apps offers 15 GB storage space per user. More about storage limits can be found here.
G Suite offers a troubleshooter which asks questions to help pinpoint where the problem could be. Sometimes things may get inadvertently overlooked. The questions often help. The troubleshooter link can be found here.
Often email logs in general including Google Apps contain details for possible causes such as delivery failure. Mail logs are a good place to check for errors and potential causes.
If a mailbox cannot receive email, the mail server should still send a response to the sender as to why their email could not be delivered. A good test is to simply try sending an email from another email address that can send/receive email to the mailbox that is not receiving new emails. Then check the sending mailbox later (including spam/trash folder) to see if a bounce back message was received. The bounce back message should contain details as to why the email was rejected by the mail server/mail account.
If all recommendations for troubleshooting fail, please provide the email account that is failing to receive emails and any details of errors/rejection notices that you may have ran across while troubleshooting.