We discovered a change in rest api responses in the latest release of TM1 which lead to incompatibility with older versions of Apliqo UX
https://documentation.apliqo.com/m/WhitePapers/l/1685682-newsflash-tm1-version-11-8-20-and-above-pa-local-2-0-917
If you upgrade to TM1 server 11.8.020 or newer then Apliqo UX must also be upgraded to 2023.05 or newer.