Loops in the hierarchy structure not allowed

What causes this issue?

Cash deconcentration occurs within one of the tables corresponding to
one of the header trees: One or more bank accounts have exactly one
superior clearing account. The same applies one level higher: One or
more clearing accounts have exactly one superior clearing account. The
target account is settled on the highest hierarchy level. It is
therefore the clearing account on the highest hierarchy level.
No loops are allowed within this structure as otherwise the algorithm
for the optimization of the account balances runs in an endless loop.
Optimization must always go from the bottom to the target account at
the top of the hierarchy specified.
In this case, such a loop was discovered in the hierarchy. The simplest
loop occurs when the bank account and the corresponding clearing
account are identical.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Please check account table TTRCD and correct the incorrect entries!
<DS:TRAN.TRCD>Execute Function</>

Error message extract from SAP system. Copyright SAP SE.