Hello.

Easiest way to figure out why the speed is blocked is going in - Menu Select - Parameter - Setting Data - Spindle Data

Here it will say the reason for and eventual maximum spindle speed

For example here the limit is due LIMS=1000 shown in Limit, G96, G961, G97

You will most likely see one of these fields showing 3175, then marking it will show the reason

Like here it shows that the maximum limit in regards to Parameter is due to MD35130

Best Regards

Riddersholm

Can't see anything obvius that would cause this to happen.

Next approach would be to check in the drive parameters if there is a parameter that overrides the NC parameter.

unfortunately you did not include this in the .arc 

For example p322 

Also Safely-Limited Speed (SLS) can cause a axis speed block but I do not believe you're setup has this function active.

Best Regards 

Riddersholm

Hello.

Here is your problem :)