If you decided to remove Magento 2 SMTP Extension by MagePal, please follow the steps below.

Remove Extension Files

Removing files instruction depends on the way the SMTP extension has been installed in.

1. If you can find the extension files in the folder

app/code/MagePal/GmailSmtpApp

then remove this folder.

2. If the extension was installed via the composer and its files located in the folder

vendor/magepal/magento2-gmailsmtpapp

then run the composer CLI command to remove it

composer remove magepal/magento2-gmailsmtpapp

Once extension files have been removed, run these Magento CLI commands:

php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy

Remove Extension Data (optional)

Attention! This will clean all SMTP configurations.

1. Just in case please make a full backup (dump) of your Magento 2 database.

2. Run the next MySQL queries to remove the extension data. E.g. you can use phpMyAdmin for this purpose.

DELETE FROM setup_module WHERE module = "MagePal_GmailSmtpApp"; 
DELETE FROM core_config_data WHERE path LIKE 'system/gmailsmtpapp';