Adobe Flash is an old technology stille employed by some financial websites in spite of it being the number 1 cause of malware infestation.
We strongly suggest you don't use any sites using Flash but if you really need to you will find that Chrome will disable Flash at intervals for the above reasons.
See below on how to re-enable.
When a problem occurs, click the padlock next to the site address (see below) and choose Site Settings.
Find Flash in the list and change the dropdown on the right to Allow.