Gmail won't connect

I have been using EMclient for about 15 months and suddenly my gmail won’t connect. We have tried taking the account off, adding it back, deleting, rebooting and adding and nothing helps.
We did give access to gmail to use it too.
Please help!
Thank you

Try temporarily turning off your Anti-Virus and VPN if either are running.

@AIG When you add in the Gmail account (using the automatic wizard) do you get up to the part where you click “Allow” access button on the “Sign in with Google” GUI in the Browser as in the below 1st screenshot below.

Also once you have allowed access with Google, you should see eM Client in your Google Security / Permissions as in the 2nd screenshot below.

Note:- If you have allowed eM Client access to your Google account and you cannot send or receive email, then you have some sort of eg: optional resident program running interfering with eM Client.

Optional Firewalls / Security programs can sometimes block mail clients (if not configured correctly). Also as @sunriseal advised sometimes also optional Antivirus and VPNs can interfere as well. So disable any of those temporarily to test if causing the issue.

(Allow access to Gmail in the browser when asked in EMC setup wizard).

(eM Client should be showing in Google Third Party Permissions after allowing access).

I have a similar issue Gmail IMAP Server become unavailable with Avast Mail protection but doesn’t effect Outlook account the only solution at the moment is to turn off the Avast Mail protection to receive your mail how ever you can still send email add event… only the incoming mail are affected.