Go to Nintendo UK's website, log in, try to purchase something, with AdGuard enabled you'll get an error message, with AdGuard disabled the website works.
The information below is automatically generated. Do not delete it.
Custom userscripts:
https://userscripts.adtidy.org/release/disable-amp/1.0/disable-amp.meta.js
https://userscripts.adtidy.org/release/adguard-extra/1.0/adguard-extra.meta.js
Screenshot 1

Screenshot 2

Information | value
--- | ---
Platform: | Android 11
AdGuard product: | AdGuard for Android v3.5 nightly 3 (17)
Browser: | Chrome
Stealth mode options: | Strip URLs from tracking parameters,
Self-destructing third-party cookies (0)
AdGuard mode: | VPN
Filtering quality: | High-quality
HTTPS filtering: | enabled
DNS requests blocking: | enabled
Filters: | Ad Blocking:
AdGuard Base,
AdGuard Mobile Ads
Privacy:
AdGuard Tracking Protection
Social Widgets:
AdGuard Social Media
Annoyances:
AdGuard Annoyances
Custom filter subscriptions: |
I see this error without AdGuard(+ UK VPN)

@AdguardTeam/filters-maintainers please take a look.
I see this error without AdGuard(+ UK VPN)
I see the same error.
@Alex-302 @AdamWr You prolly need to link a Nintendo Switch to your account. Do you guys have one or should I make a dummy account and log into my Switch with it?
@domebacsi I checked with account.
Could you please check which filter causes an issue?
@Alex-302 Oops, the problem was that I set the "Self-destructing third-party cookies" to 0
Coupld you please check these rules with "Self-destructing third-party cookies" = 0?
@@||api.ec.nintendo.com^$stealth
@@||api.accounts.nintendo.com^$stealth
@Alex-302 Same error message
EDIT without the "api." at the beginning of the URLs it works
Ok.