If any error message appears while accessing your Gmail account that you have configured with the eM client, then read the troubleshooting instructions given below then fix the em client gmail error on your PC.
First, check if you have configured the Gmail account with eM client correctly.
To make sure that, re-check the settings.
If you find any mistakes, correct it and then check if the em client gmail issue has been resolved.
If the IMAP error is still displayed on your system screen, make sure that the less secure applications are enabled.
To check it, follow the instructions given below.
Open your system’s web browser and navigate to the Gmail account login page.
Enter the required credentials in the given field and click the Sign in button to solve the em client gmail.
Once you are successfully signed in to your Gmail account, locate your account icon and select it.
Click the My Account button. Now, the Control, protect, and secure your account, All-in-one place window will appear on the screen.
Locate the Connected apps & sites option in the Sign-in & Security section.
Scroll down the screen and check if the Allow less secure apps: OFF option is enabled.
If it is disabled, click the toggle button beside it to enable the option. This should resolve the em client gmail issue.