When I attempt to Update All Data, my Indices dataset gives the following errors with the Yahoo provider...

Message:
Updating DataSet Indices ...
Preparing requests ...
Requests are ready to go.
Yahoo session cookie cached
Updating Security Names for 43 symbols...
Error updating Security Names. Invalid URI: The Uri string is too long.
[7] ^FCHI Error: Invalid URI: The Uri string is too long.
[9] ^GDAXI Error: Invalid URI: The Uri string is too long.
[1] ^AORD Error: Invalid URI: The Uri string is too long.
[0] ^AEX Error: Invalid URI: The Uri string is too long.
[8] ^FTSE Error: Invalid URI: The Uri string is too long.
[6] ^DJI Error: Invalid URI: The Uri string is too long.
[4] ^BSESN Error: Invalid URI: The Uri string is too long.
[2] ^ATX Error: Invalid URI: The Uri string is too long.
[8] ^JKSE Error: Invalid URI: The Uri string is too long.
[2] ^MERV Error: Invalid URI: The Uri string is too long.
[4] ^KS11 Error: Invalid URI: The Uri string is too long.
[5] ^BVSP Error: Invalid URI: The Uri string is too long.
[9] ^MID Error: Invalid URI: The Uri string is too long.
[3] ^BFX Error: Invalid URI: The Uri string is too long.
[0] ^HSI Error: Invalid URI: The Uri string is too long.
[7] ^GSPC Error: Invalid URI: The Uri string is too long.
[0] ^NDXE Error: Invalid URI: The Uri string is too long.
[7] ^NSEI Error: Invalid URI: The Uri string is too long.
[0] ^NYA Error: Invalid URI: The Uri string is too long.
[7] ^NZ50 Error: Invalid URI: The Uri string is too long.
[2] ^MXX Error: Invalid URI: The Uri string is too long.
[6] ^IBEX Error: Invalid URI: The Uri string is too long.
[2] ^RLV Error: Invalid URI: The Uri string is too long.
[0] ^OSX Error: Invalid URI: The Uri string is too long.
[6] ^RUI Error: Invalid URI: The Uri string is too long.
[2] ^RUT Error: Invalid URI: The Uri string is too long.
[0] ^SML Error: Invalid URI: The Uri string is too long.
[6] ^SSMI Error: Invalid URI: The Uri string is too long.
[2] ^STI Error: Invalid URI: The Uri string is too long.
[0] ^TWII Error: Invalid URI: The Uri string is too long.
[6] ^VAY Error: Invalid URI: The Uri string is too long.
[4] ^N225 Error: Invalid URI: The Uri string is too long.
[2] ^VIX Error: Invalid URI: The Uri string is too long.
[0] ^VXN Error: Invalid URI: The Uri string is too long.
[6] ^XAU Error: Invalid URI: The Uri string is too long.
[2] FTSEMIB.MI Error: Invalid URI: The Uri string is too long.
[4] 000001.SS Error: Invalid URI: The Uri string is too long.
[5] ^NDX Error: Invalid URI: The Uri string is too long.
[9] ^N300 Error: Invalid URI: The Uri string is too long.
[8] ^MSH Error: Invalid URI: The Uri string is too long.
[7] ^RUA Error: Invalid URI: The Uri string is too long.
[1] ^IXIC Error: Invalid URI: The Uri string is too long.
[3] ^OEX Error: Invalid URI: The Uri string is too long.
Update completed (0.597 sec)
----------------

Cannot reproduce. Must be a temporary glitch on their side. Please restart WLD and retry later.

Updating DataSet test ...
Preparing requests ...
Requests are ready to go.
Yahoo session cookie cached
Updating Security Names for 43 symbols...
Security Names updated.
[0] ^AEX 7111 bars 31.08.2020 7111 bars added
[1] ^BSESN 5701 bars 31.08.2020 5701 bars added
[3] ^ATX 6882 bars 31.08.2020 6882 bars added
[4] ^BFX 7449 bars 31.08.2020 7449 bars added
[2] ^AORD 9121 bars 01.09.2020 9121 bars added
[1] ^DJI 8971 bars 31.08.2020 0 bars added
[0] ^BVSP 6764 bars 31.08.2020 6764 bars added
[1] ^GSPC 23277 bars 31.08.2020 0 bars added

Cancelling update, please wait ...

Update cancelled (6.135 sec)

Yes, it seems to work now. I did restart it multiple times before creating the post so it must have been something Yahoo fixed on their side.