Irrespective of under what license/licensed use category you operate radio equipment (‘station’), irrespective of whether you are end user of provided equipment or you establish/maintain/operate the ‘station’, you are ultimately responsible for how it’s used, whether it’s fit for use operationally speaking, and for being obligated to act on any (irrespective of how genuine you believe of it) any issues or complaints and within what your licensed use allows, rectify or seek assistance to do so.
For a technical level user (defined by license, not your personal level or perception of ability), this means you are obligated to investigate as far as you can legally, any issues you discover about your station or come to light (as notified by others) that may or may not affect the integrity and operational conformity and stability of your operation. This will require effort on your part and is mandatory as much it is if you are formally cautioned or actioned to rectify a situation officially.
You are ultimately responsible and where you find it’s beyond your capability, you seek competent assistance to further rectification - ignorance or lacking the ability to sort it yourself is no defense for continuing at odds with the dilemma.
As a non technical grade user, you are obligated to seek certified and authorised assistance since in most categories of non-tech licensed use, aside from replacing plug in feeders/feeder patch cords or in-line (in the feeder) permitted functional items, it’s a black box situation.
You may be permitted to do limited antenna adjustment, siting adjustment or resonance adjustment where the permitted item has manufactured adjustment for this purpose, but otherwise, if it can’t be unplugged and substituted by permitted replacement without breaking into the ‘black box’, you’ll need to seek certified assistance to rectify.
Clearly there’s a Grand Canyon sized difference between the extent in which you can and be expected to instigate rectification actions, between technical licensed and nontechnical grade licensed users, but the responsibility to act upon and action rectification measures is common and absolute to all.
If you are a technical grade licensee, and are asked to assist with rectification measures or to assist with investigating an issue, most tech licenses obligated you to assist in as far as you can without interfering with TA certified operation or status of the equipment - however, if you are a certified technician/engineer currently permitted to test/repair and recertify such equipment and have the means, you can offer to resolve a black box fault or break the seal to internationally investigate and rectify. You’ll need to recertify it as repaired and (where fixed) operating back to factory certified state before you reconfigure it back to operational users-permitted operational configuration.
But regardless of what license you operate under, if you can’t immediately rectify the matter and need to seek rectification measures, you are also obligated to cease using it on-air until you can without causing undue issues that may be caused by the fault condition. If it ends up being decommissioned/condemned (where your use of requires certification/TA compliant equipment) then it’s game over - you’ll either need to accept alternative legally usable alternative methods or replace at your cost.
Where the situation is due to a potential interference issue, you’ll be legally obligated to instigate rectification where you are the source and the affected aren’t victims of inherent design weakness in receivers or electronics.
But, in most countries and regions I have operated in, you are not legally required to (at your cost) instigate rectification and a solution that fixes their half of the problem where it’s a 50/50 situation or entirely of their equipment fallibilities. You meet your legal obligation in such an instance by aiming to help them resolve their half of the problem (where practical and feasible), informing them of the situation and who to contact if they believe there is a valid case entirely due to your operation.
If you are seen to be making due efforts, and at least do what’s reasonably practical, if a formal agency instigates an investigation, you’ll be on the right side of acting responsibly and it’ll be accounted for where the agency actions against you.
Where they, formal investigators, cannot determine or see you made any effort at all and are partially or fully at fault - they are entitled to act as though you intentionally avoided taking action or disregarded your responsibility.
Where an issue regards conduct and use rather than a technical matter - without a doubt and unquestionably, you are legally and morally and ethically responsible for good conduct and usage of the station, whether it’s you operating or allowing a qualifying guest user to use your station.
As a precaution, aside from the common sense aspect of assessing letting any individuals or groups use your station, it’s in your interest to permit (where you do) under supervision and preferably your supervision. You may choose to recognise that one of the guest users may qualify as a suitable supervisor - but if in doubt on any level, do your own supervision because you’ll be liable to actions (where actioned) where the station is abused.
So regardless of your license and grade of operation, there’s a lot more to your responsibility than signing a license and selecting the right channel and knowing what button does what on your equipment.
So beware, be in the loop in as far as the above stuff is applied in your region (I tried to keep it as generic and universal as practical) and keep within the guidelines and mandates that you are expected to comply with.