After signing, do not use the back button. Wait until the main window shows “Success” and let it redirect by itself. If the loop starts, start the transaction from the TAMM home dashboard, not a deep link.
Sign out of TAMM, clear only *.tamm.abudhabi and related cookie domains, then re-login. Ensure system clock is auto-sync; clock skew can invalidate the signing token.
Try another browser channel (Edge vs Chrome) to exclude extension interference.