Hello, thanks a lot for your prompt answer.
Reverting to 6.4.1 did not change anything but I forgot to mention that
I had to upgrade to php 8.0 from 7.4. This is because of end of support by my internet supplier on php 7.4. WHen reverting temporarily to 7.4 the Fatal error disappears and my website is on again. So it seems to me that perhaps there is a problem with php 8 and cleantalk plugin ?
SIncerly
Richard
