Sendgrid api key cannot be entered in the SMTP settings

The sendgrid API key can be added as a password in Sugar in order to configure:
https://sendgrid.com/docs/for-developers/sending-email/sugarcrm/

As you pointed out the API key is too long for the password field, this issue is resolved in 10.3 ( https://portal.sugarondemand.com/#supp_Bugs/82737 ) where the field length is increased however the following workaround will also allow to save that in the current versions:

1. Navigate to Admin > System Email Settings
2. Click ‘Change password’ to display the password field
3. Right click in the password field and select ‘Inspect’ or ‘Inspect Element’ (depending on the browser)
4. The Developer Console should show up on the right/bottom/separate window showing the HTML elements on the page
5. Double click on the HTML element [maxlength=”64”] and change this to 80 characters instead and hit ENTER
6. Enter your password in the password field and select ‘Save’ at the top of the page
7. Send a test message to confirm that the changes are valid