HTTP codes
1xx - Hold up
2xx - All good
3xx - Redirection
4xx - User messed up
5xx - Server messed up
502/503/504 - Third-party messed up
This is Ezra. He was happily building a new app in his PDI when a 502 error appeared on his screen.
When he saw the message he started to panic.......
Fortunately, Ezra found the solution before the stress took over.
Ezra navigated to Developer Portal to check the status of his PDI.
Now he knows that PDIs typically cycle through three states:
- Offline
- Refreshing instance
- Online
- Hibernating
Ezra discovered that if an instance is Offline, a simple click of the Refresh button is all it takes. As the status changed to Refreshing instance, Ezra grabbed a glass of water to refresh himself too. Within a few minutes, both he and his PDI were ready to continue!
Hibernating: 504 Gateway Time-out
Ezra also learned that sometimes things aren't so simple.
If a PDI is undergoing unscheduled maintenance, it’s a situation out of his control that can last for several days.
When this happens, Ezra knows he has two choices:
- Patient: wait for the maintenance to finish (email notifications available),
- Impatient: Release the current instance and request a brand-new one (potential data lose).
Because Ezra is smart and keeps regular backups, he can simply request a new PDI, import his data, and get right back to building his smashing app!
His friend Silas doesn't have any backup, but they both found out that they might access the PDI with /login.do
https://yourinstance.service-now.com/login.doAnd it was clear that they can access a PDI during the maintenance, that gave them chance to make the missing backup before requesting the new instance for Silas as well.
Ezra and Silas are are both back to building their apps by coding, low-coding, and no-coding happily ever after...
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EDIT 16.04.2026: I have encountered a new state "504 Gateway Time-out", this wasn't known to me when I originally posted it. The resolution is the same as for 502, check the PDI status and either refresh your instance or wait a bit..
EDIT 18.05.2026: broken link to Dev Portal was fixed.
EDIT 27.07.2026: added screenshot for Hibernating + added the HTTP codes in the begginning.
