{"id":19023786,"date":"2026-09-18T19:30:55","date_gmt":"2026-09-18T19:30:55","guid":{"rendered":"https:\/\/wordpress.org\/support\/topic\/gmail-oauth-error-400-redirect_uri_mismatch\/"},"modified":"2026-09-18T19:30:55","modified_gmt":"2026-09-18T19:30:55","slug":"gmail-oauth-error-400-redirect_uri_mismatch","status":"publish","type":"topic","link":"https:\/\/wordpress.org\/support\/topic\/gmail-oauth-error-400-redirect_uri_mismatch\/","title":{"rendered":"Gmail OAuth Error 400: redirect_uri_mismatch"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">I&#8217;m using WP Mail SMTP 4.9.0 with the Google\/Gmail mailer and manual OAuth setup. Reauthorization fails with Google Error 400: <code>redirect_uri_mismatch<\/code>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">My Google OAuth client is a Web Application, is enabled and in Production, and its Authorized Redirect URI is exactly:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><code>https:\/\/connect.wpmailsmtp.com\/google\/<\/code><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">That same URI appears in WP Mail SMTP.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The Client ID configured in WP Mail SMTP matches the OAuth client in my Google Cloud project.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">However, Google&#8217;s OAuth error page after authorization shows a <strong>different Client ID<\/strong>, beginning with <code>59408480254-...<\/code>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Can you confirm whether that second Client ID belongs to the WP Mail SMTP <code>connect.wpmailsmtp.com<\/code> intermediary, and why Google is reporting a redirect URI mismatch when my configured redirect URI matches exactly?<\/p>\n","protected":false},"template":"","class_list":["post-19023786","topic","type-topic","status-publish","hentry","topic-tag-authorization","topic-tag-gmail","topic-tag-oauth","topic-tag-redirect_uri_mismatch"],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/19023786","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic"}],"about":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/topic\/19023786\/revisions"}],"wp:attachment":[{"href":"https:\/\/wordpress.org\/support\/wp-json\/wp\/v2\/media?parent=19023786"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}