Hey @Mindaugas,
You could solve this by bypassing the meeting id and name input by using the following url as your iFrame src, which takes you right into the meeting,
https://zoom.us/wc/{{ meetindID }}/join?prefer=1&un={{ base64Encoded Name }}
Example
<iframe src="https://zoom.us/wc/{{ meetindID }}/join?prefer=1&un=TWluZGF1Z2Fz" sandbox="allow-forms allow-scripts" allow="microphone; camera; fullscreen"></iframe>
Let me know if this helps!
Thanks,
Tommy