S21 ultra Poor signal strength

[yvonneyen]

Upgraded my phone from oppo to S21. Happily exploring this new gadget , however, ended up will keep loading when do browsing. 

I then use the same sim card to return to Oppo. The Same location, oppo has no issue of browsing but the S21 is suck.

 A 5k gadget and end up cannot use as smart phone. What else left?

Any solution?

[Minaamina]

Try to change the old sim card to new sim card

[yvonneyen]

Alright, will try

[khtannnnnnnnnn]

It might be also because oppo support budget bands while samsung support high end bands because each phone's supported bands vary

[yvonneyen]

I have changed sim card and work well now.