John Baro1 wrote:
Since updating to Monterey (from 10.14 on an iMac), I can no longer share links from Safari to Messages. The dialog pops up, and I can enter a name and sometimes type in the text box, but the buttons don't work. If I try to click the Send or Cancel button, the dialog box jumps to a slightly different location, then it becomes completely inactive. The only way to dismiss the dialog is by pressing Esc. This happens 100% of the time.
Don't use the share option—
try copy and paste directly into the Message and compare your results.
there has been some speculation Share > Messages ceases to function due to data corruption in the Contacts database as it relates to iCloud.
You can try signing out of iCloud and back in again
Sign out of iCloud on your iPhone, iPad, iPod touch, Apple TV, Mac ...
To trouble shoot further you can:
—SafeBoot How to use safe mode on your Mac - Apple Support
Takes a bit longer to get to the login screen, does a quick disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache, etc.
Login and test. Reboot as normal and test. Caches get rebuilt automatically.
In Safe mode third party system modifications and system accelerations are disabled, it removes malware, etc hampering smooth operation, however a reboot will put it back to normal mode.
This test will tell you if third party interference; extensions etc are not loaded in safe boot mode.
if no insight ot resolve—
Call Customer Support (800) MY–APPLE (800–692–7753)
or on line Apple Support