If using Internet Explorer you could try this.
Go to the TOOLS menu and choose "Compatibility View Settings" and then add the MyArchicad website address to the list.
I had similar trouble on a completely unrelated website and this fixed the problem (I was using Internet Exploree 11 out of interest).
Barry.
One of the forum moderators.
Versions 6.5 to 26
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11