Each time I try to 'publish online' InDesign 2021 crashes. Any suggestions
Which OS and version?
How much RAM and spare disk capacity do you have?
Have you tried resetting the InDesign preferences?
OS is Windows 10 - latest update.
8GB RAM and 125GB available on the Hard Drive
I suggest you increase your RAM to at the very least to 16GB and make more disk space available, this should help your crashing issue (and also, as has been suggested), trash your InDesign preferences.