Investigate testnet payer report failures

[mkysel]

https://sepolia.basescan.org/address/0x9de0b8C883c01F28A0F3d39De90c098F0941176f

Desired outcomes:

• why is this failing?
• should we alert on this?
• fix this

[fbac]

Those transactions can be inspected in BlockScout which shows raw traces, such as https://base-sepolia.blockscout.com/tx/0x372d52b3b4df8cc38282bd1ef8d2dfeba9ec3e8109b9d5a170ab5bf7f7ac00f6?tab=raw_trace

The output field is a hex encoded field which shows the error code "0x84e23433... params"

On this case 0x84e23433 is the signature of InvalidStartSequenceId(uint64,uint64).

Those failures are expected and will happen continuously. XMTPD traces the tx and mark these payer reports with submission status 3 to not loop over them anymore.

[mkysel]

Additional data point from the PayerReportManager inspector: payer reports for originator 10 (the group message migrator, GroupMessageOriginatorID = 10) appear stuck since January 14th with no new settlements.

This is consistent with the rate misconfiguration described in #286. The active rate (Rate [1], effective 2025-08-05) sets storageFee = 1,754,412,880 pD/byte/day — identical to its own startTime timestamp, almost certainly set by mistake. This charges ~$17M per hourly settlement report, driving the migrator payer (0x96d2bdc2A14c1075F86918E2E6385CB85917c569) to −$1.22B in debt over 6 days of observed activity (Feb 25 – Mar 3, 2026).

The January 14th cutoff likely coincides with when Rate [1] became operationally active or when the migrator payer's balance crossed some threshold that caused downstream failures.

Two issues are at play:

1. Wrong rates (RateRegistry testnet rates are misconfigured — storageFee set to a Unix timestamp, charging billions to migrator #286) — storageFee is ~8 orders of magnitude too high, needs a corrected rate entry
2. xmtpd int64 overflow (xmtpd#1768) — settlement amounts above ~$9.22M overflow int64 in currency.FromMicrodollars, causing xmtpd to silently drop 70 of 107 recent settlement ledger entries

Fixing the rates in the RateRegistry should unblock originator 10 report settlements going forward.