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https://support.google.com/accounts/answer/6010255
A blog from Atlassian of 19th APR: https://community.atlassian.com/t5/Jira-articles/ATTN-Changes-required-for-Jira-mail-servers-using-Google-email/ba-p/2005850
any mail server set up in Jira via a username and account password with a personal Google email account will not work from 30th May 2022
Atlassian Server/DC docs on configuring OAuth 2.0 to receive mail
Jira 8.13+ is required (https://docsjira.microsoftatlassian.com/browse/en-us/exchange/clients-and-mobile-in-exchange-online/deprecation-of-basic-authentication-exchange-onlineJRASERVER-63917).