FSTL153 - The Fastly ACL Has Reached Its Entry Limit

Agent error code #FSTL153 indicates the ACL is full, so the grant could not be added. Fastly caps an ACL at 1,000 entries and documents no self-service way to raise it.

Unlike a rate limit (#FSTL005), waiting does not clear this. Something has to leave the ACL.

Common causes include:

• More concurrent grants than the ACL can hold
• Static entries added by hand taking up the budget
• Two Knocs sharing one ACL, so they fill it together

Steps to Resolve

1. In the Fastly control panel, open the ACL and check how much of it is static configuration rather than knocknoc: entries. Move static entries to a second ACL and reference both
2. Shorten the Knoc's maximum grant duration so entries clear sooner
3. Split the load across more than one ACL, with one Knoc per ACL
4. If you need a higher limit, contact Fastly support

The Knoc wizard's Validate connection step reports the entry count, and the agent logs a warning once an ACL passes 800 entries.

Still Having Issues?

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