🚨 Error: Cannot read property 'then' of null

[ampprojectbot]

Details

Error report: link
First seen: Apr 24, 2020
Frequency: ~ 429/day

Stacktrace

Error: Cannot read property 'then' of null
    at then (https://raw.githubusercontent.com/ampproject/amphtml/2004252135000/extensions/amp-a4a/0.1/amp-ad-network-base.js:81:11)
    at layoutCallback (https://raw.githubusercontent.com/ampproject/amphtml/2004252135000/src/custom-element.js:1151:39)
    at fn (https://raw.githubusercontent.com/ampproject/amphtml/2004252135000/src/utils/promise.js:75:12)
    at https://raw.githubusercontent.com/ampproject/amphtml/2004252135000/src/utils/promise.js:74:9
    at tryResolve (https://raw.githubusercontent.com/ampproject/amphtml/2004252135000/src/custom-element.js:1151:22)
    at layoutCallback (https://raw.githubusercontent.com/ampproject/amphtml/2004252135000/src/service/resource.js:918:18)
    at callback (https://raw.githubusercontent.com/ampproject/amphtml/2004252135000/src/service/vsync-impl.js:470:16)
    at callTask_ (https://raw.githubusercontent.com/ampproject/amphtml/2004252135000/src/service/vsync-impl.js:426:8)

Notes

@zhouyx modified src/custom-element.js:1150-1151 in #15410 (May 18, 2018)
@jridgewell modified src/utils/promise.js:75-78 in #15143 (May 8, 2018)
@zhouyx modified src/custom-element.js:1150-1151 in #15410 (May 18, 2018)
@jridgewell modified src/service/resource.js:915-923 in #20814 (Feb 14, 2019)
@jridgewell modified src/service/vsync-impl.js:470-471 in #20836 (Feb 14, 2019)

Seen in:

• 04-25 Experimental (2135)

Possible assignees: @jridgewell, @zhouyx

/cc @ampproject/release-on-duty

[rcebulko]

This appears to be a dupe of #21116 with a stacktrace that has slightly changed since. Closing.