Can't run on Autopilot

[JDavidLewis 0]

Sorry, I'm probably being really dumb.
I don't seem to be able to turn on the autopilot in my Boeing 737-200Adv.
I get a + sign if I hover over the switch on the SP177 panel, but it simple won't click on.
Is there a fix for this , am I missing something, >
There are notes in my release saying to "see the checklist page" but this does not appear to carry any info on solving this problem.
LOVE the plane, Love the rest of the VC but ...
Thank you in hopes.

Edited February 24, 2023 by Ray Proudfoot
trun changed to run in topic title.

[C2615 319]

Have you release all force on yoke? if you are on keyboard make sure it's trimmed and elevator have to be manually move back to neutral position.