Steps to Reproduce:

Start minecraft.

Choose account

Select marketplace

Observed Results:

The 'scanning' animation plays for 45 seconds then shows "We're unable to connect to the Marketplace. Maybe check your Internet connection?"

Expected Results:

Marketplace should show (the internet is working)

Notes:

Issue only affects two of the accounts on the Nintendo - one child account and my account. Two other child accounts are unaffected - the 3rd child account was added today and has no problem accessing marketplace.

Issue was originally seen as one of the '-9 errors' referred to in MCPE-62421 and private issue MCPE-78636 tagged for Kelly. And, although the -9 is no longer seen, the issue of not being able to access the marketplace is still persisting with the same problematic accounts (been going on for more than a year now).

All child accounts are active with the Nintendo Switch Online package - my account is the admin\parent account for them.

None of the accounts has a Microsoft Account - these are only being used with the Nintendo profiles (all on the same device).

The issue of internet connectivity is further disproved if I choose either 'Attribution' or 'Licensed Content' from the Settings->Profile section from either of the problematic accounts - both of these happily go off the the internet and display the content in the browser view.

As an additional test, from the main menu, switching to 'Local Network' using the Y button, I can switch to Local Network within a single second. However, switching back to 'Online Network' shows the 'Enabling Online Network' animation - after about 8 seconds a small window showing 'Loading' flashed up for less than a second and then disappears to continue to show the 'Enabling Online Network' animation which never stops - I also cannot go back\cancel from here - only option is to press Home button and close the game.

Probably no surprise that the problematic accounts also don't show their Nintendo Switch Friends online when they are also playing minecraft - rendering multiplay impossible. The problematic accounts are able to play online with other Nintendo games (e.g. Animal Crossing New Horizons) so online play is working for these account - the issue is that Minecraft seems to think that two of the accounts have no internet connectivity when clearly they do.

If this is of any use ... at the bottom of the Profile section ATS:0 and MCID:<blank> are shown for just both problematic accounts - the working accounts show ATS:1 and MCID:<16-digit-hex-number> (CID:<blank> is shown for all accounts).

Switch firmware is up to date - v11.0.1