> ## Documentation Index > Fetch the complete documentation index at: https://docs.upflow.io/llms.txt > Use this file to discover all available pages before exploring further. # Troubleshooting Customer Portal Links > Resolve common customer portal link errors in Upflow, including expired tokens, HTTPS warnings, security alerts and broken redirects from email reminders. When sending email reminders to your customers, you can insert their dedicated Upflow portal link, using our collection tag "Customer portal link". ⚠️ **Important:** Each reminder generates a new token, which defines the link’s validity period. Learn more [here](/en-us/customer-portal/customer-portal/my-customers-portal-links-validity). Sometimes your customers (or even your team) may encounter errors or security alerts when opening these links. Below are the most common issues, their causes, and how to solve them.   ## Your connection is not private Your Connection Isn't Private ###  Why this happens * Your portal link is sent with an `http://` address instead of `https://` * Your customer’s browser flags the link as “Not secure”   ### Solution: Ensure HTTPS links is enabled 1. Go to **Settings > Deliverability** in Upflow. 2. Check the **HTTPS links** option. Enable HTTPS Links Ensure this is enabled in your Upflow Settings > Deliverability. If your DNS configuration is properly configured, this setting should be enabled by default (learn more here: [Deliverability - HTTPS links.](/en-us/collection-and-collaboration/emails/deliverability-https-links)   #### I can't enable the HTTPS links **Case 1: Deliverability option blocked** * You see this option when opening Deliverability Settings: Deliverability Menu Solution: Configure and verify your DNS records. Learn how [here](/en-us/collection-and-collaboration/emails/sending-emails). **Case 2: DNS configuration invalid** * One or more DNS records are invalid/incorrect, preventing the option to be enabled. * **Solution**: Share the generated records with your IT team so they can update your domain settings.   ## Customer portal not found Customer Portal Not Found Error ### Why this happens * Portal access is disabled for the customer. * They clicked a link that was sent before the portal access was disabled.   ### Solution: Reactivate portal access 1. Go to the customer’s detail page in Upflow. 2. Under **Payments > Options**, check the portal setting. 3. Reactivate the portal if needed. 4. Send a new email reminder or campaign to generate a fresh link. Payment Options Customer Page ## Invalid link Portal Invalid Link Error ### Why this happens * The link token has expired\   ### Solutions #### 1 - Re-send the customer portal link From the Customer details page, click “Preview the customer portal”, copy the URL (containing a newly generated token), and send it to your customer via an Ad hoc email, for example.\   #### 2 - Increase link validity If this is a recurring issue for your customers, you can increase the portal links duration according to your needs, and processes: 1. Go to **Settings > Customer portal**. 2. Increase the default link duration (learn more [here](/en-us/customer-portal/customer-portal/my-customers-portal-links-validity)). 3. Send a new email reminder or campaign to generate a fresh link.