diff --git a/doc/settings/configuration.md b/doc/settings/configuration.md
index b637b9aeadafa46972c214160fcfebe421cf9ed6_ZG9jL3NldHRpbmdzL2NvbmZpZ3VyYXRpb24ubWQ=..a0d64c770ddd3b7acbdddd594028e54f5a79e548_ZG9jL3NldHRpbmdzL2NvbmZpZ3VyYXRpb24ubWQ= 100644
--- a/doc/settings/configuration.md
+++ b/doc/settings/configuration.md
@@ -644,7 +644,7 @@
 
 1. Create a project in Sentry.
 1. Find the
-   [Data Source Name (DSN)](https://docs.sentry.io/product/sentry-basics/concepts/dsn-explainer/)
+   [Data Source Name (DSN)](https://docs.sentry.io/concepts/key-terms/dsn-explainer/)
    of the project you created.
 1. Edit `/etc/gitlab/gitlab.rb`:
 
@@ -655,7 +655,7 @@
    gitlab_rails['sentry_environment'] = 'production'
    ```
 
-   The [Sentry environment](https://docs.sentry.io/product/sentry-basics/concepts/environments/)
+   The [Sentry environment](https://docs.sentry.io/concepts/key-terms/environments/)
    can be used to track errors and issues across several deployed GitLab
    environments, for example, lab, development, staging, and production.
 
@@ -659,7 +659,7 @@
    can be used to track errors and issues across several deployed GitLab
    environments, for example, lab, development, staging, and production.
 
-1. Optional. To set custom [Sentry tags](https://docs.sentry.io/product/sentry-basics/concepts/enrich-data/)
+1. Optional. To set custom [Sentry tags](https://docs.sentry.io/concepts/key-terms/enrich-data/)
    on every event sent from a particular server, the `GITLAB_SENTRY_EXTRA_TAGS`
    an environment variable can be set. This variable is a JSON-encoded hash representing any
    tags that should be passed to Sentry for all exceptions from that server.
diff --git a/doc/settings/smtp.md b/doc/settings/smtp.md
index b637b9aeadafa46972c214160fcfebe421cf9ed6_ZG9jL3NldHRpbmdzL3NtdHAubWQ=..a0d64c770ddd3b7acbdddd594028e54f5a79e548_ZG9jL3NldHRpbmdzL3NtdHAubWQ= 100644
--- a/doc/settings/smtp.md
+++ b/doc/settings/smtp.md
@@ -237,9 +237,9 @@
 
 ### SMTP.com
 
-You can use the [SMTP.com](https://www.smtp.com/) email service. [Retrieve your sender login and password](https://kb.smtp.com/article/1043-my-account-1)
+You can use the [SMTP.com](https://www.smtp.com/) email service. [Retrieve your sender login and password](https://knowledge.smtp.com/s/article/My-Account)
 from your account.
 
 To improve delivery by authorizing `SMTP.com` to send emails on behalf of your domain, you should:
 
 - Specify `from` and `reply_to` addresses using your GitLab domain name.
@@ -241,9 +241,9 @@
 from your account.
 
 To improve delivery by authorizing `SMTP.com` to send emails on behalf of your domain, you should:
 
 - Specify `from` and `reply_to` addresses using your GitLab domain name.
-- [Set up SPF and DKIM for the domain](https://kb.smtp.com/article/1039-email-authentication-spf-dkim-dmarc).
+- [Set up SPF and DKIM for the domain](https://knowledge.smtp.com/s/article/Email-authentication-SPF-DKIM-DMARC).
 
 ```ruby
 gitlab_rails['smtp_enable'] = true
@@ -258,7 +258,7 @@
 gitlab_rails['gitlab_email_reply_to'] = 'user@your.gitlab.domain.com'
 ```
 
-Check the [SMTP.com Knowledge Base](https://kb.smtp.com/) for further assistance.
+Check the [SMTP.com Knowledge Base](https://knowledge.smtp.com/s/) for further assistance.
 
 ### SparkPost
 
@@ -478,7 +478,7 @@
 
 ### SendGrid with API Key authentication
 
-If you don't want to supply a username/password, you can use an [API key](https://docs.sendgrid.com/for-developers/sending-email/getting-started-smtp):
+If you don't want to supply a username/password, you can use an [API key](https://www.twilio.com/docs/sendgrid/for-developers/sending-email/getting-started-smtp):
 
 ```ruby
 gitlab_rails['smtp_enable'] = true
@@ -1198,7 +1198,7 @@
 
 ### NIFCLOUD ESS
 
-[SMTP Interface](https://pfs.nifcloud.com/spec/ess/smtp.htm).
+[SMTP Interface](https://docs.nifcloud.com/ess/spec/smtp.htm).
 
 ```ruby
 gitlab_rails['smtp_enable'] = true
diff --git a/doc/settings/ssl/index.md b/doc/settings/ssl/index.md
index b637b9aeadafa46972c214160fcfebe421cf9ed6_ZG9jL3NldHRpbmdzL3NzbC9pbmRleC5tZA==..a0d64c770ddd3b7acbdddd594028e54f5a79e548_ZG9jL3NldHRpbmdzL3NzbC9pbmRleC5tZA== 100644
--- a/doc/settings/ssl/index.md
+++ b/doc/settings/ssl/index.md
@@ -582,7 +582,7 @@
    sudo gitlab-ctl reconfigure
    ```
 
-For more information on HSTS and NGINX, see <https://www.nginx.com/blog/http-strict-transport-security-hsts-and-nginx/>.
+For more information on HSTS and NGINX, see <https://blog.nginx.org/blog/http-strict-transport-security-hsts-and-nginx>.
 
 ## Install custom public certificates