🚨 Error: Failed to read the 'cssRules' property from 'CSSStyleSheet': Cannot access rules

Details
---
**Error report:** [link](http://go/ampe/CJ35p7f70qyfAw)
**First seen:** Oct 14, 2021
**Frequency:** ~ 7,789/day

Stacktrace
---

Error: Failed to read the 'cssRules' property from 'CSSStyleSheet': Cannot access rules

    at cssRules (amp-animation/0.1/parsers/keyframes-extractor.js:38:18)

    at scanStyle (amp-animation/0.1/parsers/keyframes-extractor.js:18:22)

    at this (amp-animation/0.1/web-animations.js:467:41)

    at createKeyframes_AMP_PRIVATE_ (amp-animation/0.1/web-animations.js:447:24)

    at callback (amp-animation/0.1/web-animations.js:604:10)

    at callback (amp-animation/0.1/web-animations.js:1004:19)

    at withVars (amp-animation/0.1/web-animations.js:602:18)

    at callback (amp-animation/0.1/web-animations.js:988:19)

    at withTarget (amp-animation/0.1/web-animations.js:597:16)

/cc @ampproject/release-on-duty