The Telescope home page might sometimes not load and instead display a 503 HTTP error like this
HTTP Error 503. The service is unavailable.
If you're an OnDemand customer, please raise a ticket with support for assistance with this issue.
This can be due to issues with SAML SSO, or WebObjects workers not running, or the workers not being able to restart successfully. Rebooting the TSWeb servers will fix the issue if the worker processes are failing to restart. If you're an On-premise customer and would like assistance with this issue, please create a support ticket.
As this is a Sev-1 issue, please follow the process listed in the relevant KB article and create a ticket on PLNP JIRA with type SaaS Incident and priority Showstopper, mentioning the name & type of the customer installation(OnDemand/On-premise).
Once the fixes are applied, the home page should not go unresponsive because of the listed causes in this article.