Altium tell me Off Grid Net
The most common cause of this issue is that you are using components designed on, say, a metric grid but your schematic is on a standard grid (or vice versa). You can change the schematic grid by opening the schematic, go to Design --> Document Options, click the Units tab and select the checkbox next to "Use ____ Unit System" (select the one that is not currently selected). Make sure the grid itself matches the grid that the components were created on (in the libraries).

If the problem persists (just with different off-grid pins this time) then chances are you have some components created on a metric grid and some created on a standard grid. This is one of the reasons why I recommend ALWAYS making your own libraries, rather than using third-party ones. You just can't get consistency from using multiple third-party libraries.

Your best bet would be to build a new library and recreate the components you are using. Make sure they're all created on the same grid that you want your final schematic to be on, and use your custom library exclusively.